Python Ireland presents December Talks @ The Science Gallery
Hi All, When: Wed 8th December, 19:00-20:00 Where: The Science Gallery What: - Microsoft Openness Campaign by Liam Cronin - Windows Azure -- The Nuts and Bolts by Stephen Fitzmaurice - Pub - Trinity Capital Hotel More info: http://www.python.ie/meetup/2010/dec_2010_talks__the_science_gallery/ This event is free and all levels welcome. Cheers, /// Vicky ~ ~~ http://irishbornchinese.com ~~ ~~ http://www.python.ie ~~ ~ -- http://mail.python.org/mailman/listinfo/python-announce-list Support the Python Software Foundation: http://www.python.org/psf/donations/
[Venue Update] Python Ireland's Oct Talks - Wed 13th Oct, 19:00
Hi All, Apologies in advance, the venue for October talks is now at The Central Hotel on Exchequer Street. The Science Gallery is closed due to construction of their next exhibition. I've added the update event on the site: http://www.python.ie/meetup/2010/oct_2010_talks__the_central_hotel/ Cheers, /// Vicky ~ ~~ http://irishbornchinese.com ~~ ~~ http://www.python.ie ~~ ~ -- http://mail.python.org/mailman/listinfo/python-announce-list Support the Python Software Foundation: http://www.python.org/psf/donations/
ANN: Roundup Issue Tracker 1.4.16 released
I'm proud to release version 1.4.16 of Roundup which introduces some minor features and, as usual, fixes some bugs: Features: - allow trackers to override the classes used to render properties in templating per issue2550659 (thanks Ezio Melotti) - new mailgw configuration item subject_updates_title: If set to no a changed subject in a reply to an issue will not update the issue title with the changed subject. Thanks to Arkadiusz Kita and Peter Funk for requesting the feature and discussing the implementation. http://thread.gmane.org/gmane.comp.bug-tracking.roundup.user/10169 - new rdbms config item sqlite_timeout makes the previously hard-coded timeout of 30 seconds configurable. This is the time a client waits for the locked database to become free before giving up. Used only for SQLite backend. - new mailgw config item unpack_rfc822 that unpacks message attachments of type message/rfc822 and attaches the individual parts instead of attaching the whole message/rfc822 attachment to the roundup issue. Fixed: - fixed reporting of source missing warnings - relevant tests made locale independent, issue2550660 (thanks Benni Bärmann for reporting). - fix for incorrect except: syntax, issue2550661 (thanks Jakub Wilk) - No longer use the root logger, use a logger with prefix roundup, see http://thread.gmane.org/gmane.comp.bug-tracking.roundup.devel/5356 - improve handling of 'gt;' when URLs are converted to links, issue2550664 (thanks Ezio Melotti) - fixed registration, issue2550665 (thanks Timo Paulssen) - make sorting of multilinks in the web interface more robust, issue2550663 - Fix charset of first text-part of outgoing multipart messages, thanks Dirk Geschke for reporting, see http://thread.gmane.org/gmane.comp.bug-tracking.roundup.user/10223 - Fix handling of incoming message/rfc822 attachments. These resulted in a weird mail usage error because the email module threw a TypeError which roundup interprets as a Reject exception. Fixes issue2550667. Added regression tests for message/rfc822 attachments with and without configured unpacking (mailgw unpack_rfc822, see Features above) Thanks to Benni Bärmann for reporting. - Allow search_popup macro to work with all db classes, issue2550567 (thanks John Kristensen) - lower memory footprint for (journal-) import If you're upgrading from an older version of Roundup you *must* follow the Software Upgrade guidelines given in the maintenance documentation. Roundup requires python 2.3 or later (but not 3+) for correct operation. To give Roundup a try, just download (see below), unpack and run:: roundup-demo Release info and download page: http://cheeseshop.python.org/pypi/roundup Source and documentation is available at the website: http://roundup.sourceforge.net/ Mailing lists - the place to ask questions: http://sourceforge.net/mail/?group_id=31577 About Roundup = Roundup is a simple-to-use and -install issue-tracking system with command-line, web and e-mail interfaces. It is based on the winning design from Ka-Ping Yee in the Software Carpentry Track design competition. Note: Ping is not responsible for this project. The contact for this project is rich...@users.sourceforge.net. Roundup manages a number of issues (with flexible properties such as description, priority, and so on) and provides the ability to: (a) submit new issues, (b) find and edit existing issues, and (c) discuss issues with other participants. The system will facilitate communication among the participants by managing discussions and notifying interested parties when issues are edited. One of the major design goals for Roundup that it be simple to get going. Roundup is therefore usable out of the box with any python 2.3+ (but not 3+) installation. It doesn't even need to be installed to be operational, though an install script is provided. It comes with two issue tracker templates (a classic bug/feature tracker and a minimal skeleton) and four database back-ends (anydbm, sqlite, mysql and postgresql). -- http://mail.python.org/mailman/listinfo/python-announce-list Support the Python Software Foundation: http://www.python.org/psf/donations/
[Ann] Celery 2.1 stable released
Hey!
Celery 2.1.0 was just uploaded to PyPI!
This is a backward compatible release in the 2.x series,
and is an recommended upgrade for all users.
What is Celery?
Celery is an open source asynchronous task queue/job queue based on
distributed message passing. It is focused on real-time operation, but
supports scheduling as well.
The execution units, called tasks, are executed concurrently on one or
more worker nodes. Tasks can execute asynchronously (in the background)
or synchronously (wait until ready).
For more information go to http://celeryproject.org
Highlights
* Periodic task schedule can now be stored in a database,
and changes will be reflected at runtime (only supported by django-celery
at the moment, but this can also be used in general)
http://celeryq.org/docs/userguide/periodic-tasks.html#periodic-tasks
* New web monitor using the Django Admin interface.
Can also be used by non-Django users.
http://celeryq.org/docs/userguide/monitoring.html#django-admin-monitor
* Periodic tasks now supports arguments and keyword arguments.
* celeryctl: A new command line utility to inspect and manage worker
nodes.
http://celeryq.org/docs/userguide/monitoring.html#celeryctl-management-utility
* AMQP Backend: Now supports automatic expiration of results.
* Task expiration: A date and time which after the task will be considered
expired
and will not be executed.
* Lots of bugs fixed.
* Lots of documentation improvements.
Changes
===
The full list of changes are available in the changelogs:
* celery: http://celeryq.org/docs/changelog.html
* django-celery: http://celeryq.org/docs/django-celery/changelog.html
Download
* celery: http://pypi.python.org/pypi/celery/2.1.0
* django-celery: http://pypi.python.org/pypi/django-celery/2.1.0
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+47 98435213 | twitter.com/asksol }.
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Evolutionary Algorithms in Python (EAP) First Public Release (0.6)
Hi everyone, We are proud to announce the first public release of EAP, a library for doing Evolutionary Algorithms in Python. You can download a copy of this open source project at the following web page. http://deap.googlecode.com EAP has been built using the Python and UNIX programming philosophies in order to provide a transparent, simple and coherent environment for implementing your favourite evolutionary algorithms. EAP is very easy to use even for those who do not know much about the Python programming language. EAP uses the object oriented paradigm that is provided by Python in order to make development simple and beautiful. It also contains a 15 illustrative and diversified examples, to help newcomers to ramp up very quickly in using this environment. EAP is part of the DEAP project, that also includes some facilities for the automatic distribution and parallelization of tasks over a cluster of computers. The D part of DEAP, called DTM, is under intense development and currently available as an alpha version. DTM currently provides two and a half ways to distribute workload on a cluster or LAN of workstations, based on MPI and TCP communication managers. This public release (version 0.6) is more complete and simpler than ever. It includes Genetic Algorithms using any imaginable representation, Genetic Programming with strongly and loosely typed trees in addition to automatically defined functions, Evolution Strategies (including Covariance Matrix Adaptation), multiobjective optimization techniques (NSGA-II and SPEA2), easy parallelization of algorithms and much more like milestones, genealogy, etc. We are impatient to hear your feedback and comments on that system at deap-users at googlegroups dot com Best, François-Michel De Rainville Félix-Antoine Fortin Marc-André Gardner Christian Gagné Marc Parizeau Laboratoire de Vision et Systèmes Numériques Département de génie électrique et génie informatique Université Laval Quebec City (Quebec), Canada -- http://mail.python.org/mailman/listinfo/python-announce-list Support the Python Software Foundation: http://www.python.org/psf/donations/
Re: del() function - cannot find documentation
Chris Rebert c...@rebertia.com wrote:
On Thu, Oct 7, 2010 at 1:12 PM, mafeu...@gmail.com wrote:
there is following python script:
mine = { 1: sd, 2: mk }
del(mine[1])
print mine
the problem is I cannot find any information about del() function in
python 2.7 documentation.
is it a documentation bug or I misunderstand something about del()?
del is a *statement*, *not* a function:
http://docs.python.org/reference/simple_stmts.html#the-del-statement
This kind of confusion is, in my opinion, the primary reason why
parentheses should never be used with del and return, as we so commonly
see.
--
Tim Roberts, t...@probo.com
Providenza Boekelheide, Inc.
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Re: frozendict (v0.1)
kj no.em...@please.post writes:
In 87hbgxlk67@gmail.com Arnaud Delobelle arno...@gmail.com writes:
A simple fix is to use hash(frozenset(self.items())) instead.
Thanks for pointing out the hash bug. It was an oversight: I meant
to write
def __hash__(self):
return hash(sorted(tuple(self.items(
But sorted returns a list!
so you need rather: hash(tuple(sorted(self.items(
However, it still won't work because some keys may be incomparable.
E.g., try with {1:'a', 1j:'b'}
--
Arnaud
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Re: harmful str(bytes)
On Thu, 07 Oct 2010 23:33:35 +0200 Hallvard B Furuseth h.b.furus...@usit.uio.no wrote: The offender is bytes.__str__: str(b'foo') == b'foo'. It's often not clear from looking at a piece of code whether some data is treated as strings or bytes, particularly when translating from old code. Which means one cannot see from context if str(s) or %s % s will produce garbage. This probably comes from overuse of str(s) and %s. They can be useful to produce human-readable messages, but you shouldn't have to use them very often. I really wish bytes.__str__ would at least by default fail. Actually, the implicit contract of __str__ is that it never fails, so that everything can be printed out (for debugging purposes, etc.). Regards Antoine. -- http://mail.python.org/mailman/listinfo/python-list
Re: [Python-ideas] [Python-Dev] Inclusive Range
On Wed, Oct 06, 2010 at 05:28:13PM -0400, Terry Reedy wrote:
On 10/6/2010 7:14 AM, Antoon Pardon wrote:
That right-hand-half-open intervals (i.e. a= i b, equivalently [a,
b) ), which are what Python uses, are to be preferred.
(See aforelinked PDF: http://www.cs.utexas.edu/users/EWD/ewd08xx/EWD831.PDF)
This specifically discusses subsequences of 'natural numbers'.
Sure, but I don't think we should limit ourselves to subsequence of
natural numbers. It is my impression that orginally slices were
also limited to indicating subsequences of natural numbers. This
original limitation, has guided its semantics that resulted in
what we have now,
The problem is that the slice notation is sometimes handy in situations where
an open interval doesn't allow easily to mark what you want.
For instance I have at one time implemted a Tree. This is a dict like
structure
but it allows to visit the keys in order. Because there is an order, slice
notation can make sense. e.g. if T is a tree with names as keys,
T['bea':'mike']
is a subtree where we have for each key that 'bea'= key 'mike'.
But what if I wanted a subtree where 'mike' was still included, but nothing
further?
Or what if the keys were floats or tuples and I wanted an inclusive upper
boundary?
Strings and tuples are not natural numbers, but do have least
members ('' and ()), so the bottom end had better be closed.
Why? The fact that we have a bottom element in the item space,
doesn't imply that the sequence I need is easiest defined by
using an inclusive lower limit. What if I wanted all none-empty
strings/tuples keys in the tree? The easiest way to specify that
would be by saying the key needed to be larger than the empty
string/tuple. If the keys were strings I could fudge it by starting
with chr(0), but what value should use as start, if I wanted all
non-empty tuples?
Since
substracting strings and tuples in meaningless, the argument of
having stop-start == number of items does not apply. Floats can be
subtracted, but the result in not a count of included items. So
write the .__getitem__ method of *your* class how it best fits your
use-cases.
My use cases depend on the specific problem I need to solve. Sometimes
the problem is easiest solved with an inclusive limit, sometimes it
is with an exclusive limit. The slice notation although at first sight
a natural way to specify the boundaries, seems on closer inspection
to be too limited.
Just be aware that an inclusive upper boundary means that
s[a:b]+s[b:c] will no longer be s[a:c] because b will be duplicated.
Let me also point out integer slices for builtins are adjusted to
that they refer to actual slice positions. This is harder to do with
strings;-). Also, suppose you want all strings beginning with 'a' or
'b'. With an open upper end, Tree['a':'c'] will do that. With closed
upper end, you would need
Tree['a':'bbb'] or somesuch.
Yes I know. I'm starting to think about aproaching this in a different
manner.
And what if you needed the reverse sequence. If you start with inclusive
limit,
the reverse of a= item= b is b= item= a. If the second limit is to be
exclusive the reverse of a= item b becomes (b - 1)= item (a - 1).
Slices with positive strides can be defined and understood in terms
of slice positions before the first item, between all successive
pairs of items and after the last. By this same definition and
understanding, s[b:a:-1] should be reversed(s[a:b]), which is what
many expect. It is not because the definition is given in terms of
the translation into indexes and blindly applied to the case of
negative strides without the needed adjustment. I consider this a
design mistake, at least for many uses. (Extended slices, if not
extended slicing, were added for numerical Python and they may have
wanted the current definition for negative strides.)
I agree that this is a design mistake. Personnaly I find it horrible
that in the following expression: L[a:b:-1], it is impossible to
give a numeric value to b, that will include L[0] into the reversed
slice. It is the reason why I avoid reversed slices as much as
possible.
--
Antoon Pardon
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Re: add bitbucket repo url to install_requires
On 05/10/2010 12:43, Julian wrote: I'm developing a django app which depends on an app in a private bitbucket repository, for example ssh://h...@bitbucket.org/username/my-django-app. is it possible to add this url to the list of install_requires in my setup.py? tried various possibilities, but none worked. That would be abhorent. Don't even try to do that. If the app has a setup.py, specify the name passed to setup() in setup.py in install_requires. Then you just need to make sure a distribution of the above is available when you want to install. What I would do: - clone the above repo - in your local clone do: python setup.py sdist - put the resulting .tgz somewhere safe and accessible - install using your package manager of choice and pass the somewhere safe and accessible location by way of --find-links or equivalent. cheers, Chris -- Simplistix - Content Management, Batch Processing Python Consulting - http://www.simplistix.co.uk -- http://mail.python.org/mailman/listinfo/python-list
Re: Many newbie questions regarding python
Rogério Brito wrote: class C: f = 1 def g(self): return f I get an annoying message when I try to call the g method in an object of type C, telling me that there's no global symbol called f. If I make g return self.f instead, things work as expected, but the code loses some readability. Is there any way around this or is that simply a matter of life? class C: f =1 creates the 'C.f ' name. When 'f' is used in g, you'll get then an error. class C: f = 1 def g(self): return C.f is the obvious solution. However it can be slightly improved. f is a class attribute, meaning it's common to all instances of the C class. Thus g would be a class method, and is here declared liek a instance method (the instance being self). class C: f = 1 @classmethod def g(cls): return cls.f c1 = C() c2 = C() print c1.f, c2.f # f is not an attribute of c1 nor c2, thus the lookup will try in the class and find C.f 1 1 c1.f = 10 # this create the c1 instance attribute f != class attribute f c2.f = 20 # this create the c2 instance attribute f != class attribute f print c1.f, c2.f, c1.g(), c2.g(), C.f 10 20 1 1 1 Cheers, JM -- http://mail.python.org/mailman/listinfo/python-list
Re: frozendict (v0.1)
On 10/08/2010 02:23 AM, kj wrote: I imagine that frozenset is better than sorted(tuple(...)) here, but it's not obvious to me why. dicts are unsorted. That means their item-order is undefined. So are sets. If you want a hash that is independent from the order of items, you could ensure the items are always in the same order when you do the hashing; or you could use a hashing algorithm that ignore item order. As creating a `frozenset` is probably more efficient than sorting, that is the preferred solution. Here's my implementation suggestion: class frozendict(dict): def _immutable_error(self, *args, **kwargs): raise TypeError(%r object is immutable % self.__class__.__name__) __setitem__ = __delitem__ = clear = pop \ = popitem = setdefault = update = _immutable_error def __hash__(self): return hash(frozenset(self.iteritems())) Only 9 lines :-) Jonas -- http://mail.python.org/mailman/listinfo/python-list
Re: frozendict (v0.1)
In 4cae667c$0$29993$c3e8da3$54964...@news.astraweb.com Steven D'Aprano st...@remove-this-cybersource.com.au writes: On Fri, 08 Oct 2010 00:23:30 +, kj wrote: Because it's always better to use a well-written, fast, efficient, correct, well-tested wheel than to invent your own slow, incorrect wheel :) IOW, don't you worry your little head about why. -- http://mail.python.org/mailman/listinfo/python-list
Re: Many newbie questions regarding python
Rogério Brito rbr...@ime.usp.br wrote in message news:i8lk0n$g3...@speranza.aioe.org... My first try to write it in Python was something like this: v = [] for i in range(20): v[i] = 0 Unfortunately, this doesn't work, as I get an index out of bounds when trying to index the v list. Python can't grow a list by assigning to out-of-bound elements (although, being the language it is, there is probably a way of achieving that by redefining how [] works...) What is the Pythonic way of writing code like this? So far, I have found many v = [0 for i in range(20)] v = [0] * 20 v = [] for i in range(20): v.append(0) What should I prefer? Any other alternative? v=[0,0,0,0,0, 0,0,0,0,0, 0,0,0,0,0, 0,0,0,0,0] will also work. But none of these appeal too much. I would probably do: def newlist(length,init=0): return [init]*length ... v=newlist(1000) (with the proviso that someone mentioned when the init value is complex: you might not get unique copies of each). If possible, I would like to simply declare the list and fill it latter in my program, as lazily as possible (this happens notoriously when one is using a technique of programming called dynamic programming where initializing all positions of a table may take too much time in comparison to the filling of the array). A sparse array? Even if an array could be constructed by assigning to arbitrary elements, the gaps created would still need filling in with None or Unassigned. 2 - If I declare a class with some member variables, is is strictly necessary This is where I bail out... -- Bartc -- http://mail.python.org/mailman/listinfo/python-list
Re: frozendict (v0.1)
In 878w29kxjp@gmail.com Arnaud Delobelle arno...@gmail.com writes:
E.g., try with {1:'a', 1j:'b'}
I see. Thanks for this clarification. I learned a lot from it.
I guess that frozenset must have some way of canonicalizing the
order of its elements that is dependent on their Python values but
not on their comparability. My first thought was that they are
ordered according to their hash values, but this theory doesn't
hold:
abc = ('a', 'b', 'c')
sorted(map(hash, abc))
[-468864544, -340864157, -212863774]
map(hash, frozenset(abc))
[-468864544, -212863774, -340864157]
I.e. the ordering of the elements in the frozenset does not correspond
to the ordering of their hashes in either direction. Hmmm.
I tried to understand this by looking at the C source but I gave
up after 10 fruitless minutes. (This has been invariably the
outcome of all my attempts at finding my way through the Python C
source.)
I guess the take-home message is that frozenset is a more general
way to canonicalize an iterable object than sorting, even though
the reasons for this still remain a mystery to me... Then again,
just looking at the voodoo that goes into algorithms for computing
hashes fills me with despair. As much as I dislike it, sooner or
later I'll have to go on faith.
~kj
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Re: harmful str(bytes)
Arnaud Delobelle writes: Hallvard B Furuseth h.b.furus...@usit.uio.no writes: I've been playing a bit with Python3.2a2, and frankly its charset handling looks _less_ safe than in Python 2. (...) With 2.late conversion Unicode - string the equivalent operation did not silently produce garbage: it raised UnicodeError instead. With old raw Python strings that was not a problem in applications which did not need to convert any charsets, with python3 they can break. I really wish bytes.__str__ would at least by default fail. I think you misunderstand the purpose of str(). It is to provide a (unicode) string representation of an object and has nothing to do with converting it to unicode: That's not the point - the point is that for 2.* code which _uses_ str vs unicode, the equivalent 3.* code uses str vs bytes. Yet not the same way - a 2.* 'str' will sometimes be 3.* bytes, sometime str. So upgraded old code will have to expect both str and bytes. In 2.*, str-unicode conversion failed or produced the equivalent character/byte data. Yes, there could be charset problems if the defaults were set up wrong, but that's a smaller problem than in 3.*. In 3.*, the bytes-str conversion always _silently_ produces garbage. And lots of code use both, and need to convert back and forth. In particular code 3.* code converted from 2.*, or using modules converted from 2.*. There's a lot of such code, and will be for a long time. -- Hallvard -- http://mail.python.org/mailman/listinfo/python-list
Re: mantissa and exponent in base 10
Jason Swails wrote:
s = ('%%%ig' % sigfigs) % n # double-% cancels the %
Thanks! I see that the parenthesis can be dropped, too:
'%%.%ig' % 3 % 4.23456e-5
'4.23e-05'
/c
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Re: harmful str(bytes)
Antoine Pitrou writes: Hallvard B Furuseth h.b.furus...@usit.uio.no wrote: The offender is bytes.__str__: str(b'foo') == b'foo'. It's often not clear from looking at a piece of code whether some data is treated as strings or bytes, particularly when translating from old code. Which means one cannot see from context if str(s) or %s % s will produce garbage. This probably comes from overuse of str(s) and %s. They can be useful to produce human-readable messages, but you shouldn't have to use them very often. Maybe Python 3 has something better, but they could be hard to avoid in Python 2. And certainly our site has plenty of code using them, whether we should have avoided them or not. I really wish bytes.__str__ would at least by default fail. Actually, the implicit contract of __str__ is that it never fails, so that everything can be printed out (for debugging purposes, etc.). Nope: $ python2 -c 'str(u\u1000)' Traceback (most recent call last): File string, line 1, in ? UnicodeEncodeError: 'ascii' codec can't encode character u'\u1000' in position 0: ordinal not in range(128) And the equivalent: $ python2 -c 'unicode(\xA0)' Traceback (most recent call last): File string, line 1, in ? UnicodeDecodeError: 'ascii' codec can't decode byte 0xa0 in position 0: ordinal not in range(128) In Python 2, these two UnicodeEncodeErrors made our data safe from code which used str and unicode objects without checking too carefully which was which. Code which sort the types out carefully enough would fail. In Python 3, that safety only exists for bytes(str), not str(bytes). -- Hallvard -- http://mail.python.org/mailman/listinfo/python-list
Re: frozendict (v0.1)
On 10/08/2010 03:27 PM, kj wrote:
I tried to understand this by looking at the C source but I gave
up after 10 fruitless minutes. (This has been invariably the
outcome of all my attempts at finding my way through the Python C
source.)
It's not you. CPython's code is ... [censored]
Anyway, you don't even need to read C code to understand how sets are
implemented.
There is a (now deprecated) Python module, Libs/set.py, that has
implementations for `Set` and `ImmutableSet` (nowadays `set` and
`frozenset`).
The implementation strategy you can see there is quite simple. The code
uses dictionary keys to store the set items and ignores the dictionary
values, so that `.add(value)` is implemented as `._dict[value] =
some_value_nobody_cares_about`.
Here comes a very limited example set implementation using a dict:
class PrimitiveSet(object):
def __init__(self):
self._dict = {}
def add(self, value):
self._dict[value] = True
def __contains__(self, value):
return value in self._dict
def __repr__(self):
return 'PrimitiveSet(%r)' % self._dict.keys()
s = PrimitiveSet()
'hello' in s
False
s.add('hello')
'hello' in s
True
s
PrimitiveSet(['hello'])
s.add(tuple(xrange(10)))
s
PrimitiveSet([(0, 1, 2, 3, 4, 5, 6, 7, 8, 9), 'hello'])
s.add(xrange(5))
s
PrimitiveSet([(0, 1, 2, 3, 4, 5, 6, 7, 8, 9), xrange(5), 'hello'])
This has a few implications for sets:
* dict keys are unordered/sorted. so are sets.
* dict keys are unique. same for set values.
* dict keys have to be hashable (immutable). same for sets values.
So far our implementation is not hashable, and we need a custom
implementation for __hash__ (because dicts aren't hashable, so we cannot
re-use dictionary methods).
There is one requirement for set hashes: they have to be independent of
the item order (there *is* an order in memory of course, and it may vary
depending on the order assignments to our dict are done).
Here is an extract from the Python set implementation,
`BaseSet._compute_hash`:
def _compute_hash(self):
# Calculate hash code for a set by xor'ing the hash codes of
# the elements. This ensures that the hash code does not depend
# on the order in which elements are added to the set. [...]
result = 0
for elt in self:
result ^= hash(elt)
return result
Hope this helps :-)
Jonas
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Re: frozendict (v0.1)
In i8loa2$3o...@reader1.panix.com kj no.em...@please.post writes:
At any rate, using your [i.e. Arnaud's] suggestions in this and
your other post, the current implementation of frozendict stands
at:
class frozendict(dict):
for method in ('__delitem__ __setitem__ clear pop popitem setdefault '
'update').split():
exec
def %s(self, *a, **k):
cn = self.__class__.__name__
raise TypeError('%%s' object is not mutable %% cn)
% method
def __hash__(self):
return hash(frozenset(self.items()))
...which is a lot nicer!
As a side comment on my own post, this is the second time in less
than a week that I find myself having to resort to exec'ing some
code generated from a template. This one is worse, because there's
nothing runtime-dependent about the code being exec'd. It sticks
in my craw somehow. It just doesn't seem quite right that at the
time of doing something as bread-and-butter as implementing a
subclass, one has to choose between explicitly writing a whole
bunch of identical methods, and exec-based hacks like what I'm
doing above. There's got to be a better to tell Python: override
all these superclass methods with this one.
Or maybe the problem here is that, in a perfect world, frozendict
would be in the standard library, as a superclass of dict lacking
all of dict's destructive methods. :)
~kj
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Re: frozendict (v0.1)
In mailman.1461.1286539843.29448.python-l...@python.org Jonas H. jo...@lophus.org writes: On 10/08/2010 02:23 AM, kj wrote: Here's my implementation suggestion: class frozendict(dict): def _immutable_error(self, *args, **kwargs): raise TypeError(%r object is immutable % self.__class__.__name__) __setitem__ = __delitem__ = clear = pop \ = popitem = setdefault = update = _immutable_error def __hash__(self): return hash(frozenset(self.iteritems())) Only 9 lines :-) Thanks, you just answered the question I just posted, while I was still writing it! ~kj -- http://mail.python.org/mailman/listinfo/python-list
Re: frozendict (v0.1)
In mailman.1463.1286546684.29448.python-l...@python.org Jonas H. jo...@lophus.org writes: Hope this helps :-) It did! Thanks! For one thing now I see that I was barking up the wrong tree in focusing on a canonical order, when, as the code you posted shows, it is actually not required for hashing. In fact, I'd come to the conclusion that frozensets had a consistent order (i.e. frozensets that were equal according to '==' would be iterated over in the same order), but now I'm not sure that this is the case. (Granted, semantically, there's nothing in the definition of a frozenset that would imply a consistent iteration order.) Thanks again! ~kj -- http://mail.python.org/mailman/listinfo/python-list
Help with pointers when calling from python to C
Hi. This is kind of a cross-product question, having to do with accessibility on Linux using ATK (AT-SPI). However, I think it really boils down to a python question: How do I pass an integer by reference to a C function? I am using Accerciser (http://live.gnome.org/Accerciser), an accessibility testing tool that has an ipython console. It uses pyatspi to interact with AT-SPI through pyORBit. I need to test my handling of atk_editable_text_insert_text(AtkEditableText *text, const gchar *string, gint length, gint *position). In the example below, the variable 'acc' has been bound (by Accerciser) to an accessible object that implements the AtkEditableText interface. The problem is that the pesky position parameter wants a pointer to an integer. I have tried all sorts of ways to get Accerciser's iPython console to accept the last parameter, but I always get: TypeError: could not marshal arg 'position'. Has anyone done this? If so, then how is it done? Here's a sample of the things I tried: In [1]: t=acc.queryEditableText() In [2]: t.getText(0,45) Out[2]: 'The quick brown fox jumps over the lazy dog.\n' In [3]: t.deleteText(10,15) Out[3]: True In [4]: t.getText(0,40) Out[4]: 'The quick fox jumps over the lazy dog.\n' In [5]: pos=10 In [6]: t.insertText(brown,5,pos) --- TypeError Traceback (most recent call last) /usr/lib/python2.6/dist-packages/pyatspi/__init__.pyc in module() 1 2 3 4 5 /usr/lib/python2.6/dist-packages/pyatspi/accessible.pyc in _inner(self, *args, **kwargs) 230 try: 231 # try calling the original func -- 232 return func(self, *args, **kwargs) 233 except ORBit.CORBA.NO_IMPLEMENT, e: 234 # raise Python exception TypeError: could not marshal arg 'position' In [7]: t.insertText(brown,5,id(pos)) --- TypeError Traceback (most recent call last) /usr/lib/python2.6/dist-packages/pyatspi/__init__.pyc in module() 1 2 3 4 5 /usr/lib/python2.6/dist-packages/pyatspi/accessible.pyc in _inner(self, *args, **kwargs) 230 try: 231 # try calling the original func -- 232 return func(self, *args, **kwargs) 233 except ORBit.CORBA.NO_IMPLEMENT, e: 234 # raise Python exception TypeError: could not marshal arg 'position' In [8]: pos=[10] In [9]: t.insertText(brown,5,pos) --- TypeError Traceback (most recent call last) /usr/lib/python2.6/dist-packages/pyatspi/__init__.pyc in module() 1 2 3 4 5 /usr/lib/python2.6/dist-packages/pyatspi/accessible.pyc in _inner(self, *args, **kwargs) 230 try: 231 # try calling the original func -- 232 return func(self, *args, **kwargs) 233 except ORBit.CORBA.NO_IMPLEMENT, e: 234 # raise Python exception TypeError: could not marshal arg 'position' In [7]: pos=array([10]) --- NameError Traceback (most recent call last) /usr/lib/python2.6/dist-packages/pyatspi/__init__.pyc in module() 1 2 3 4 5 NameError: name 'array' is not defined Thanks, Carolyn-- http://mail.python.org/mailman/listinfo/python-list
Re: Help with pointers when calling from python to C
On 10/08/2010 05:23 PM, Carolyn MacLeod wrote: How do I pass an integer by reference to a C function? That's impossible in pure Python. The only thing I can think of is a wrapper in C. -- http://mail.python.org/mailman/listinfo/python-list
Re: Many newbie questions regarding python
On 2010-10-08, BartC b...@freeuk.com wrote: Rogério Brito rbr...@ime.usp.br wrote in message news:i8lk0n$g3...@speranza.aioe.org... If possible, I would like to simply declare the list and fill it latter in my program, as lazily as possible (this happens notoriously when one is using a technique of programming called dynamic programming where initializing all positions of a table may take too much time in comparison to the filling of the array). A sparse array? Even if an array could be constructed by assigning to I agree, what the OP seems to want (whether he actually needs it or not) is a sparse array. A sparse array? Even if an array could be constructed by assigning to arbitrary elements, the gaps created would still need filling in with None or Unassigned. That is only true when attempting to address elements based on their position rather then something like rank. You could create an object with some kind of index attribute that you could search for built in. When you needed to access the element, you simply walked the list until you find the matching identifier. The spaces no longer need filling since you are not matching based on absolute position in the list. This is of course inefficient for large lists, and while there are several methods of making this method more efficient (indexing, skip linking, b-tree, etc), you can get what you want very efficiently most of the time by simply using the built in dictionary with integer keys instead of a list. -- http://mail.python.org/mailman/listinfo/python-list
Re: Eclipse/PyDev - BOM Lexical Error
Lawrence D'Oliveiro wrote: In message 87hbgyosdc@web.de, Diez B. Roggisch wrote: Lawrence D'Oliveiro l...@geek-central.gen.new_zealand writes: In message 87d3rorf2f@web.de, Diez B. Roggisch wrote: Lawrence D'Oliveiro l...@geek-central.gen.new_zealand writes: What exactly is the point of a BOM in a UTF-8-encoded file? It's a marker like the coding: utf-8 in python-files. It tells the software aware of it that the content is UTF-8. But if the software is aware of it, then why does it need to be told? Let me rephrase: windows editors such as notepad recognize the BOM, and then assume (hopefully rightfully so) that the rest of the file is text in utf-8 encoding. But they can only recognize it as a BOM if they assume UTF-8 encoding to begin with. Otherwise it could be interpreted as some other coding. Not so. The first three bytes are the flag. For example, in a .dbf file, the first byte determines what type of dbf the file is: \x03 = dBase III, \x83 = dBase III with memos, etc. More checking should naturally be done to ensure the rest of the fields make sense for the dbf type specified. MS decided that if the first three bytes = \xEF \xBB \xBF then it's a UTF-8 file, and if it is not, don't open it with an MS product. Likewise, MS will add those bytes to any UTF-8 file it saves. Naturally, this causes problems for non-MS usages, but anybody who's had to work with both MS and non-MS platforms/products/methodologies knows that MS does not play well with others. ~Ethan~ -- http://mail.python.org/mailman/listinfo/python-list
Re: Many newbie questions regarding python
On 2010-10-07, Rog??rio Brito rbr...@ime.usp.br wrote: If possible, I would like to simply declare the list and fill it latter in my program, as lazily as possible (this happens notoriously when one is using a technique of programming called dynamic programming where initializing all positions of a table may take too much time in comparison to the filling of the array). At first you say you want a list, later you say you want an array. They're two different things. Arrays are variable-length and can be heterogeneous. If what you really want is a fixed-length, homogeneous array, then use an array instead of a list: http://docs.python.org/library/array.html If I declare a class with some member variables, is is strictly necessary for me to qualify those members in a method in that class? Yes. I get an annoying message when I try to call the g method in an object of type C, telling me that there's no global symbol called f. If I make g return self.f instead, things work as expected, but the code loses some readability. That's a matter of opinion. Some of us _like_ self.f since it explicitly shows the reader that f isn't a global or local but a class or instance variable. Any time you make the reader/maintainer guess what something is, that's a bug waiting to happen. Is there any way around this or is that simply a matter of life? Well, that's how Python works. I won't comment on life. -- Grant Edwards grant.b.edwardsYow! I feel like a wet at parking meter on Darvon! gmail.com -- http://mail.python.org/mailman/listinfo/python-list
Re: frozendict (v0.1)
On Fri, 08 Oct 2010 12:10:50 +, kj wrote: In 4cae667c$0$29993$c3e8da3$54964...@news.astraweb.com Steven D'Aprano st...@remove-this-cybersource.com.au writes: On Fri, 08 Oct 2010 00:23:30 +, kj wrote: Because it's always better to use a well-written, fast, efficient, correct, well-tested wheel than to invent your own slow, incorrect wheel :) IOW, don't you worry your little head about why. Shame on you for deleting the context of my answer. You said: I imagine that frozenset is better than sorted(tuple(...)) here, but it's not obvious to me why. Because frozenset already works. Because somebody else has done the work, and debugged it, and tested it, and profiled it, and optimized it, and ensured that it is correct and fast. That saves you a lot of effort, and frees you from having to duplicate the same functionality, and debugging it, testing it, profiling it, and optimizing it. Every line of code that you can avoid writing is a win. If you're a carpenter, it is better to buy a hammer than it is to go out and dig up your own iron ore, smelt the metal, and forge it into a hammer: unless you're in the business of making hammers, you've got better things to do with your time. And if you're a programmer, you've got better things to do than write a slower, buggier version of code that already exists. If you want to know *what* the frozenset does that is better, then go read the source code. For all I know you might discover that it does the same thing as your code. It's *still* better to use frozenset, simply because it already exists. Unless you profile your code and discover that frozenset is too slow and you can do better, there is no reason not to use it, and many reasons to use it. This has nothing to do with your little head, but about code reuse. Almost the entire history of programming, from the invention of sub- routines to the open source movement, is about code reuse. -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: Many newbie questions regarding python
On 2010-10-08, Grant Edwards inva...@invalid.invalid wrote: On 2010-10-07, Rog??rio Brito rbr...@ime.usp.br wrote: If possible, I would like to simply declare the list and fill it latter in my program, as lazily as possible (this happens notoriously when one is using a technique of programming called dynamic programming where initializing all positions of a table may take too much time in comparison to the filling of the array). At first you say you want a list, later you say you want an array. They're two different things. Arrays are variable-length and can be heterogeneous. I meant _Lists_ are fixed-length and homogeneous If what you really want is a fixed-length, homogeneous array, then use an array instead of a list: http://docs.python.org/library/array.html Actually, that's not the right link either. I was thinking more of NumPy arrays, where you can create an arbitrary sized homogeneous array of a desired type (either uninitialized or filled with zeros or ones): http://www.scipy.org/Tentative_NumPy_Tutorial#head-d3f8e5fe9b903f3c3b2a5c0dfceb60d71602cf93 If you're crunching so many numbers that initializing a list is a problem, then you probably ought to be using NumPy. -- Grant Edwards grant.b.edwardsYow! for ARTIFICIAL at FLAVORING!! gmail.com -- http://mail.python.org/mailman/listinfo/python-list
Re: Many newbie questions regarding python
On 2010-10-08, Grant Edwards inva...@invalid.invalid wrote: On 2010-10-08, Grant Edwards inva...@invalid.invalid wrote: On 2010-10-07, Rog??rio Brito rbr...@ime.usp.br wrote: If possible, I would like to simply declare the list and fill it latter in my program, as lazily as possible (this happens notoriously when one is using a technique of programming called dynamic programming where initializing all positions of a table may take too much time in comparison to the filling of the array). At first you say you want a list, later you say you want an array. They're two different things. Arrays are variable-length and can be heterogeneous. I meant _Lists_ are fixed-length and homogeneous Damn. I should give up and go golfing. _Lists_ are variable-length and can be heterogenous. _Arrays_ are homogenous and sort-of fixed length. [...] I was thinking more of NumPy arrays, where you can create an arbitrary sized homogeneous array of a desired type (either uninitialized or filled with zeros or ones): http://www.scipy.org/Tentative_NumPy_Tutorial#head-d3f8e5fe9b903f3c3b2a5c0dfceb60d71602cf93 If you're crunching so many numbers that initializing a list is a problem, then you probably ought to be using NumPy. -- Grant Edwards grant.b.edwardsYow! I'm shaving!! at I'M SHAVING!! gmail.com -- http://mail.python.org/mailman/listinfo/python-list
Re: frozendict (v0.1)
On Fri, 08 Oct 2010 14:00:17 +, kj wrote:
In i8loa2$3o...@reader1.panix.com kj no.em...@please.post writes:
At any rate, using your [i.e. Arnaud's] suggestions in this and your
other post, the current implementation of frozendict stands at:
class frozendict(dict):
for method in ('__delitem__ __setitem__ clear pop popitem'
'setdefault update').split():
exec
def %s(self, *a, **k):
cn = self.__class__.__name__
raise TypeError('%%s' object is not mutable %% cn)
% method
def __hash__(self):
return hash(frozenset(self.items()))
...which is a lot nicer!
As a side comment on my own post, this is the second time in less than a
week that I find myself having to resort to exec'ing some code generated
from a template. This one is worse, because there's nothing
runtime-dependent about the code being exec'd.
Er, *all* Python classes are created at runtime. The class statement is
executed at runtime, not compile time. Not that it really matters.
But in any case, it's easy enough to avoid exec with a factory function.
The following is untested, but should work:
def no_mutate_factory(name):
def inner(self, *args, **kwargs):
cn = self.__class__.__name__
raise TypeError('%s instance is not mutable' % cn)
inner.__name__ = name
return inner
class FrozenDict(dict):
update = no_mutate_factory('update')
clear = no_mutate_factory('clear')
# ...
It's a bit messy to have to list the name of the method twice. But you
can inject the appropriate methods into the class by adding them from
outside the class block:
class FrozenDict(dict):
pass
for name in 'update clear'.split() # and the others
setattr(FrozenDict, name, no_mutate_factory(name))
del name # Avoid namespace pollution, if you care.
--
Steven
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Re: [Python-ideas] [Python-Dev] Inclusive Range
On Fri, 08 Oct 2010 10:21:16 +0200, Antoon Pardon wrote: Personnaly I find it horrible that in the following expression: L[a:b:-1], it is impossible to give a numeric value to b, that will include L[0] into the reversed slice. L = [1, 2, 3, 4, 5] L[5:-6:-1] [5, 4, 3, 2, 1] -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: harmful str(bytes)
On Fri, 08 Oct 2010 15:31:27 +0200, Hallvard B Furuseth wrote:
Arnaud Delobelle writes:
Hallvard B Furuseth h.b.furus...@usit.uio.no writes:
I've been playing a bit with Python3.2a2, and frankly its charset
handling looks _less_ safe than in Python 2. (...)
With 2.late conversion Unicode - string the equivalent operation
did not silently produce garbage: it raised UnicodeError instead.
With old raw Python strings that was not a problem in applications
which did not need to convert any charsets, with python3 they can
break.
I really wish bytes.__str__ would at least by default fail.
I think you misunderstand the purpose of str(). It is to provide a
(unicode) string representation of an object and has nothing to do with
converting it to unicode:
That's not the point - the point is that for 2.* code which _uses_ str
vs unicode, the equivalent 3.* code uses str vs bytes. Yet not the same
way - a 2.* 'str' will sometimes be 3.* bytes, sometime str. So
upgraded old code will have to expect both str and bytes.
I'm sorry, this makes no sense to me. I've read it repeatedly, and I
still don't understand what you're trying to say.
In 2.*, str-unicode conversion failed or produced the equivalent
character/byte data. Yes, there could be charset problems if the
defaults were set up wrong, but that's a smaller problem than in 3.*. In
3.*, the bytes-str conversion always _silently_ produces garbage.
So you say, but I don't see it. Why is this garbage?
b = b'abc\xff'
str(b)
b'abc\\xff'
That's what I would expect from the str() function called with a bytes
argument. Since decoding bytes requires a codec, which you haven't given,
it can only return a string representation of the bytes.
If you want to decode bytes into a string, you need to specify a codec:
str(b, 'latin-1')
'abcÿ'
b.decode('latin-1')
'abcÿ'
--
Steven
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Re: Many newbie questions regarding python
On 10/8/2010 10:15 AM Grant Edwards said... Damn. I should give up and go golfing. +1 QOTW Emile -- http://mail.python.org/mailman/listinfo/python-list
PYTHON
PLEASE LEARN ME PYTHON -- http://mail.python.org/mailman/listinfo/python-list
Re: PYTHON
On 2010-10-08, k.. m.51ah...@gmail.com wrote: PLEASE LEARN ME PYTHON Done! Please be sure to drop by sometimes to let us know how it's going, now that we've learned you Python. -s -- Copyright 2010, all wrongs reversed. Peter Seebach / usenet-nos...@seebs.net http://www.seebs.net/log/ -- lawsuits, religion, and funny pictures http://en.wikipedia.org/wiki/Fair_Game_(Scientology) -- get educated! I am not speaking for my employer, although they do rent some of my opinions. -- http://mail.python.org/mailman/listinfo/python-list
Re: if the else short form
On Oct 7, 9:23 am, Lawrence D'Oliveiro l...@geek-
central.gen.new_zealand wrote:
x = {1 : One, 2 : Two, 3 : Three}.get(i, None Of The Above)
More like:
x = {1:lambda:One, 2:lambda:Two, 3:lambda:Three}.get(i,
lambda:None Of The Above)()
i.e. deferred evaluation of selected case.
In Algol68 this would be:
x:=(i|One,Two,Three|None Of The Above)
N
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* http://sourceforge.net/projects/algol68/files
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Re: Many newbie questions regarding python
On Oct 7, 6:10 pm, Rogério Brito rbr...@ime.usp.br wrote:
Hi there.
I am used to some languages like C, but I am just a complete newbie with
Python
and, while writing some small snippets, I had encountered some problems, with
which I would sincerely appreciate any help, since I appreciate this language
to
write my running pseudocode in and I am seriously thinking of using it to
teach some algorithms classes.
1 - The first issue that I am having is that I don't seem to be able to, say,
use something that would be common for people writing programs in C: defining
a
one-dimensional vector and only initializing it when needed.
For instance, in C, I would write something like:
int v[20];
for (i = 0; i 20; i++)
v[i] = 0;
Note that I only define the vector v (and its size) at the beginning but
initialize it latter during the code per-se.
My first try to write it in Python was something like this:
v = []
for i in range(20):
v[i] = 0
Unfortunately, this doesn't work, as I get an index out of bounds when trying
to
index the v list. Of course, the main difference between the two snippets is
that, in C, I declared v to have 20 positions, while in python I initialized
it
to be the empty list and, indeed, it has an empty set of indexes.
What is the Pythonic way of writing code like this? So far, I have found many
alternatives and I would like to write code that others in the Python
community
would find natural to read. Some of the things that crossed my mind:
v = [0 for i in range(20)]
v = [0] * 20
v = []
for i in range(20): v.append(0)
What should I prefer? Any other alternative?
If possible, I would like to simply declare the list and fill it latter in my
program, as lazily as possible (this happens notoriously when one is using a
technique of programming called dynamic programming where initializing all
positions of a table may take too much time in comparison to the filling of
the
array).
2 - If I declare a class with some member variables, is is strictly necessary
for me to qualify those members in a method in that class? For instance, if I
define:
class C:
f = 1
def g(self):
return f
I get an annoying message when I try to call the g method in an object of type
C, telling me that there's no global symbol called f. If I make g return
self.f
instead, things work as expected, but the code loses some readability.
Is there any way around this or is that simply a matter of life?
I have some other questions, but I will save them for latter.
Please, keep in mind that I am a newbie in Python. Despite that, I am enjoying
the little that I know.
Thank you very much in advance,
--
Rogério Brito : rbr...@{ime.usp.br,gmail.com} : GPG key
4096R/BCFChttp://rb.doesntexist.org: Packages for LaTeX :
algorithms.berlios.de
DebianQA:http://qa.debian.org/developer.php?login=rbrito%40ime.usp.br
How about:
v = [None] * 20
That way, you're not initializing with an artifical value like 0.
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Re: if the else short form
On Oct 7, 10:36 am, BartC b...@freeuk.com wrote:
i=16
x = {1 : fna(), 2 : fnb(), 3 : fnc()}.get(i, None Of The Above)
print x
Other than efficiency concerns, sometimes you don't want the extra
side-effects.
Probably there are workarounds here too, but I suspect the syntax won't be
quite as pert as the Algol68-style example:
x = (i | Zero, One, Two | None of the above) # 0-based
/* ¢ Algol68 case clause is 1-based. ¢ */
However Algol68's CASE ~ IN ~,~,~,~ OUT ~ ESAC clause does mean that
the case items of the clause are not evaluated unless selected. Here
are some comparisons with python:
$ cat py_case.py
#!/usr/bin/env python
# -*- coding: utf-8 -*-
# This procedure evaluates all the months lengths _before_ building
the dict.
# In that case of month length, they are constants.
def days_in_month0(year, month):
return {1:31,
2:{True:29,False:28}[year%4==0 and year%100!=0 or year%400==0],
3:31,4:30,5:31,6:30,7:31,8:31,9:30,10:31,11:30,12:31
}.get(month,None)
# This procedure is closer - in behaviour - to that of the algol68
case clause.
# Keypoint being that individual month length code is not evaluated
unless called()
def days_in_month(year, month):
return {1:lambda:31,
2:lambda:{True:lambda:29,False:lambda:28}[year%4==0 and year%100!
=0 or year%400==0](),
3:lambda:31,4:lambda:30,5:lambda:31,6:lambda:30,7:lambda:
31,8:lambda:31,9:lambda:30,10:lambda:31,11:lambda:30,12:lambda:31
}.get(month,None of the above)()
for year in 1899,1900,1901,1999,2000,2001:
print %4d=%2d%(year,days_in_month0(year, 2)),
Compare with Algol 68:
Brief choice clause example:
PROC days in month = (INT year, month)UNION(INT,STRING):
(month|31,
(year%×4=0 ∧ year%×100≠0 ∨ year%×400=0|29|28),
31,30,31,30,31,31,30,31,30,31
|None of the above # or EMPTY #
);
BOLD choice clause example:
PROC days in month = (INT year, month)UNION(INT,STRING):
CASE month IN 31,
IF year MOD 4 EQ 0 AND year MOD 100 NE 0 OR year MOD 400 EQ 0 THEN
29 ELSE 28 FI,
31,30,31,30,31,31,30,31,30,31
OUT None of the above # or EMPTY #
ESAC;
[]INT years = (1899,1900,1901,1999,2000,2001);
FOR key TO UPB years DO INT year=years[key];
printf(($4d,=2d $, year, days in month(year, 2)))
OD
$ python py_case.py
1899=28 1900=28 1901=28 1999=28 2000=29 2001=28
There are also the compound IF and CASE conditional clauses:
IF condition1 THEN statements ELIF condition2 THEN statements [ ELSE
statements ] FI
brief form if IF clause: ( condition1 | statements |: condition2 |
statements | statements )
CASE switch1 IN statements, statements,... OUSE switch2 IN
statements, statements,... [ OUT statements ] ESAC
brief form of CASE statement: ( switch1 |
statements,statements,... |: switch2 | statements,statements,... |
statements )
Enjoy
NevilleDNZ
--
To download Linux's Algol68 Compiler, Interpreter Runtime:
* http://sourceforge.net/projects/algol68/files
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open file on mac
hi, sorry if it is a stupid qustio,but i cannot figure out where's the problem. i've a simpleModule: class Starter: def init(self,num): print hithere! print the answer is ,num import sys,os print path:,sys.path try: #f = open(/Users/lguerrasio/myfold/initfile.py,'r') f = open(initfile.py,'r') f.close() print huurray! except IOError: print The file does not exist, exiting gracefully print This line will always print The module is located in the same folder of initfile.py now,from terminal I import sys and add to the path the folder /Users/ lguerrasio/myfold; the I import the module and execute simpleModule.Starter().init(48) on mac I get an error if i do not give the full path of initfile.py (commented out in the code above); on windows i did not have this problem. Am I missing anything? -- http://mail.python.org/mailman/listinfo/python-list
Re: Many newbie questions regarding python
On Oct 8, 10:27 am, Steven D'Aprano st...@remove-this- cybersource.com.au wrote: v = [0 for i in range(20)] Absolutely not. Such a code snippet is very common, in fact I've done it myself, but it is a hammer solution -- to a small boy with a hammer, everything looks like a nail that needs hammering. Writing such a list comprehension is a list comp solution. v = [0] * 20 Yes, this is the solution. But the list comp version will work as expected for mutable types, whereas the 'solution' only works for immutable types. If anything, I feel like the list comp version is the correct solution because of its reliability, whereas the multiplication form feels like either a lucky naive approach or relies on the reader to know the type of the initialising value and its mutability. -- http://mail.python.org/mailman/listinfo/python-list
Re: SysLogHandler message formatting
On Oct 7, 6:18 am, Vinay Sajip vinay_sa...@yahoo.co.uk wrote: Thanks for the detailed report. I tried posting a response a couple of times, but Google appears to have swallowed it ... trying again. Sorry if it results in multiple responses. I tried to respond yesterday, but I also noticed this probelm. The SysLogHandler aims to work within RFC 5424, though that does provide for some flexibility in message formats. The SysLogHandler sends priorityformatted message, as you've observed, with the formatted message part encoded in UTF-8 with a prepended BOM if it's Unicode. I started to read RFC 5424 yesterday before posting this, but it seemed to describe a much more complex message format than SysLogHandler was producing, so I wasn't sure if that was the reference or not. I may go back and read it completely, now that I know, though. The existing SysLogHandler code seems to work OK with syslog, syslog-ng and rsyslog I agree with this, so I would normally assume that Metalog is the problem and simply stop using it. Unfortunately, I have several systems that use Metalog, and I don't want to introduce any inconsistencies by having one use something else. Switching them all would also be a hassle. - perhaps these are more forgiving than Metalog in the way they parse messages, or perhaps it's a Metalog configuration issue. I'd try posting this issue to the Metalog forum / mailing list to see what feedback they can give. I will do that; I just wanted to see what the Python stance was first. I will keep you apprised of anything determined through that route. If you do think it's a bug in SysLogHandler then please create an issue on bugs.python.org and assign it to me, so I can take a look at it After I communicate with the Metalog community, I will definitely file an issue if necessary. I didn't want to jump the gun, though. I think using an appropriate Formatter will ensure interoperability in any particular scenario. I don't especially want to hard-code any format into SysLogHandler, since a Formatter can be used to set the format flexibly. I think the only problem with doing it that way is that I wasn't initially aware that using a Formatter affected how the message is sent to Syslog, but assumed it only modified the visible portion. I will admit that, until yesterday, I knew nothing of the syslog protocol. Perhaps the best solution would be to simply document the fact that adjusting the message format can affect how the message is parsed by the syslog daemon receiving it. Thank you for your feedback. -- http://mail.python.org/mailman/listinfo/python-list
google.com/trends
google.com/trends -- http://mail.python.org/mailman/listinfo/python-list
Re: Many newbie questions regarding python
On Oct 7, 7:10 pm, Rogério Brito rbr...@ime.usp.br wrote:
Hi there.
I am used to some languages like C, but I am just a complete newbie with
Python
and, while writing some small snippets, I had encountered some problems, with
which I would sincerely appreciate any help, since I appreciate this language
to
write my running pseudocode in and I am seriously thinking of using it to
teach some algorithms classes.
1 - The first issue that I am having is that I don't seem to be able to, say,
use something that would be common for people writing programs in C: defining
a
one-dimensional vector and only initializing it when needed.
For instance, in C, I would write something like:
int v[20];
for (i = 0; i 20; i++)
v[i] = 0;
Note that I only define the vector v (and its size) at the beginning but
initialize it latter during the code per-se.
My first try to write it in Python was something like this:
v = []
for i in range(20):
v[i] = 0
Unfortunately, this doesn't work, as I get an index out of bounds when trying
to
index the v list. Of course, the main difference between the two snippets is
that, in C, I declared v to have 20 positions, while in python I initialized
it
to be the empty list and, indeed, it has an empty set of indexes.
What is the Pythonic way of writing code like this? So far, I have found many
alternatives and I would like to write code that others in the Python
community
would find natural to read. Some of the things that crossed my mind:
v = [0 for i in range(20)]
v = [0] * 20
v = []
for i in range(20): v.append(0)
What should I prefer? Any other alternative?
If possible, I would like to simply declare the list and fill it latter in my
program, as lazily as possible (this happens notoriously when one is using a
technique of programming called dynamic programming where initializing all
positions of a table may take too much time in comparison to the filling of
the
array).
Just to emphasize what Andreas said:
While
v = [0] * 20
is nice and good,
don't do this
v = [ [] ] * 20
or this
v = [ {} ] * 20
until you have played around with it on the interactive prompt to
understand how it works.
The difference of behavior of mutable vs immutable objects is one of
the main pitfalls for beginners in Python. Everything is very
consistent once you understand the assignment semantics, but it really
confuses people accustomed to other languages that work differently.
--
http://mail.python.org/mailman/listinfo/python-list
Re: Simple database explorer
On Oct 7, 7:49 am, Lawrence D'Oliveiro l...@geek- central.gen.new_zealand wrote: In message 21c99273-ed58-4f93-b98a-d9292de5d...@k10g2000yqa.googlegroups.com, dusans wrote: - all the others having ODBC drivers... ODBC seems to be something you use when you can’t use a proper database driver. yes. first i have been mixing native and odbc drivers. Now i only use odbc. Odbc is not the best but its good enought for a sql explorer. Dont know how its on unix thou -- http://mail.python.org/mailman/listinfo/python-list
Re: pywebkit - python bindings for webkit DOM (alpha)
apologies for the 3 copies of the post: mail.python.org's SMTP service was offline yesterday. just a quick update: XMLHttpRequest support has been fixed today, and the correct version of libsoup discovered which actually works. that puts PythonWebkit into a useful and useable state, despite being only 15 days old. further development is still needed, but it's still pretty exciting to be back to where the original python webkit bindings code was, from 2008, minus the cruft from the intermediate glib/gobject layer, in such a short amount of time. l. -- http://mail.python.org/mailman/listinfo/python-list
HI... WE R HOT COUPLES AND SEARCHING FOR HOT MAN, WOMAN OR COUPLES FOR REAL FUN
HI... WE R HOT COUPLES AND SEARCHING FOR HOT MAN, WOMAN OR COUPLES FOR REAL FUN JUST CLICK... http://adultfriendfinder.com/go/page/reg_form_video_03?pid=g1250650-ppc http://adultfriendfinder.com/go/page/reg_form_video_03?pid=g1250650-ppc http://adultfriendfinder.com/go/page/reg_form_video_03?pid=g1250650-ppc -- http://mail.python.org/mailman/listinfo/python-list
Re: SysLogHandler message formatting
On Oct 7, 6:18 am, Vinay Sajip vinay_sa...@yahoo.co.uk wrote: Thanks for the detailed report. I tried posting a response a couple of times, but Google appears to have swallowed it ... trying again. Sorry if it results in multiple responses. Hmm, I too seem to be experiencing this problem... The SysLogHandler aims to work within RFC 5424, though that does provide for some flexibility in message formats. The SysLogHandler sends priorityformatted message, as you've observed, with the formatted message part encoded in UTF-8 with a prepended BOM if it's Unicode. I started to read RFC 5424 yesterday before posting this, but it seemed to describe a much more complex message format than SysLogHandler was producing, so I wasn't sure if that was the reference or not. I may go back and read it completely, now that I know, though. The existing SysLogHandler code seems to work OK with syslog, syslog-ng and rsyslog I agree with this, so I would normally assume that Metalog is the problem and simply stop using it. Unfortunately, I have several systems that use Metalog, and I don't want to introduce any inconsistencies by having one use something else. Switching them all would also be a hassle. - perhaps these are more forgiving than Metalog in the way they parse messages, or perhaps it's a Metalog configuration issue. I'd try posting this issue to the Metalog forum / mailing list to see what feedback they can give. I will do that; I just wanted to see what the Python stance was first. I will keep you apprised of anything determined through that route. If you do think it's a bug in SysLogHandler then please create an issue on bugs.python.org and assign it to me, so I can take a look at it After I communicate with the Metalog community, I will definitely file an issue if necessary. I didn't want to jump the gun, though. I think using an appropriate Formatter will ensure interoperability in any particular scenario. I don't especially want to hard-code any format into SysLogHandler, since a Formatter can be used to set the format flexibly. I think the only problem with doing it that way is that I wasn't initially aware that using a Formatter affected how the message is sent to Syslog, but assumed it only modified the visible portion. I will admit that, until yesterday, I knew nothing of the syslog protocol. Perhaps the best solution would be to simply document the fact that adjusting the message format can affect how the message is parsed by the syslog daemon receiving it. Thank you for your feedback. -- http://mail.python.org/mailman/listinfo/python-list
Sys.exit in secondary threads
I've noticed that there is nothing in python's documentation regarding the use of sys.exit(code) in a non-main thread. As far as I've seen, the behaviour in this case is to simply exit the thread, without caring about the return code. in the main thread however, the return code becomes the official return code of the whole process. Is that all we have to say about sys.exit() in a multithreaded program ? Or are there corner cases I've missed ? We'd better document this anyway. Regards, Pascal -- http://mail.python.org/mailman/listinfo/python-list
open file on mac
hallo, i'm sorry if the question is very stupid, but i cannot understand what i'm doing wrong here. i have this myModule.py code class Starter: def init(self,num): print hithere! print the answer is ,num import sys,os print path:,sys.path print bye try: ##f = open(/Users/lguerrasio/_myfold/initfile.py,'r') f = open(initfile.py,'r') f.close() print huurray! except IOError: print The file does not exist, exiting gracefully print This line will always print /code the module is in the same folder of initfile from terminal, i import sys and add to the path /Users/lguerrasio/ _myfold/; then i import the module and call myModule.Starter().init(9) now,the file will be opened only if i give the full path, not if i give only the name of the file, although the folder is in the path. what am I missing? -- http://mail.python.org/mailman/listinfo/python-list
Re: ConFoo spam?
On Oct 7, 10:01 am, Jack Diederich jackd...@gmail.com [For the record ConFoo /does/ interest me, but I can't take a week and a half off to do that plus PyCon]. CooFoo is an excellent conference. Even in the non-python tracks, there are plenty of high quality talks that would be of interest to people tracking this list. I learned quite a bit last year. Raymond -- http://mail.python.org/mailman/listinfo/python-list
Unicode Support in Ruby, Perl, Python, Emacs Lisp
here's my experiences dealing with unicode in various langs.
Unicode Support in Ruby, Perl, Python, Emacs Lisp
Xah Lee, 2010-10-07
I looked at Ruby 2 years ago. One problem i found is that it does not
support Unicode well. I just checked today, it still doesn't. Just do
a web search on blog and forums on “ruby unicode”. e.g.: Source,
Source, Source, Source.
Perl's exceedingly lousy unicode support hack is well known. In fact
it is the primary reason i “switched” to python for my scripting needs
in 2005. (See: Unicode in Perl and Python)
Python 2.x's unicode support is also not ideal. You have to declare
your source code with header like 「#-*- coding: utf-8 -*-」, and you
have to declare your string as unicode with “u”, e.g. 「u林花謝了春紅」. In
regex, you have to use unicode flag such as 「re.search(r'\.html
$',child,re.U)」. And when processing files, you have to read in with
「unicode(inF.read(),'utf-8')」, and printing out unicode you have to
do「outF.write(outtext.encode('utf-8'))」. If you are processing lots of
files, and if one of the file contains a bad char or doesn't use
encoding you expected, your python script chokes dead in the middle,
you don't even know which file it is or which line unless your code
print file names.
Also, if the output shell doesn't support unicode or doesn't match
with the encoding specified in your python print, you get gibberish.
It is often a headache to figure out the locale settings, what
encoding the terminal support or is configured to handle, the encoding
of your file, the which encoding the “print” is using. It gets more
complex if you are going thru a network, such as ssh. (most shells,
terminals, as of 2010-10, in practice, still have problems dealing
with unicode. (e.g. Windows Console, PuTTY. Exception being Mac's
Apple Terminal.))
Python 3 supposedly fixed the unicode problem, but i haven't used it.
Last time i looked into whether i should adopt python 3, but
apparently it isn't used much. (See: Python 3 Adoption) (and i'm quite
pissed that Python is going more and more into OOP mumbo jumbo with
lots ad hoc syntax (e.g. “views”, “iterators”, “list comprehension”.))
I'll have to say, as far as text processing goes, the most beautiful
lang with respect to unicode is emacs lisp. In elisp code (e.g.
Generate a Web Links Report with Emacs Lisp ), i don't have to declare
none of the unicode or encoding stuff. I simply write code to process
string or buffer text, without even having to know what encoding it
is. Emacs the environment takes care of all that.
It seems that javascript and PHP also support unicode well, but i
don't have extensive experience with them. I suppose that elisp, php,
javascript, all support unicode well because these langs have to deal
with unicode in practical day-to-day situations.
--
for links, see
http://xahlee.blogspot.com/2010/10/unicode-support-in-ruby-perl-python.html
Xah ∑ xahlee.org ☄
--
http://mail.python.org/mailman/listinfo/python-list
Re: frozendict (v0.1)
kj wrote:
In 878w29kxjp@gmail.com Arnaud Delobelle arno...@gmail.com writes:
E.g., try with {1:'a', 1j:'b'}
I see. Thanks for this clarification. I learned a lot from it.
I guess that frozenset must have some way of canonicalizing the
order of its elements that is dependent on their Python values but
not on their comparability. My first thought was that they are
ordered according to their hash values, but this theory doesn't
hold:
abc = ('a', 'b', 'c')
sorted(map(hash, abc))
[-468864544, -340864157, -212863774]
map(hash, frozenset(abc))
[-468864544, -212863774, -340864157]
I.e. the ordering of the elements in the frozenset does not correspond
to the ordering of their hashes in either direction. Hmmm.
I tried to understand this by looking at the C source but I gave
up after 10 fruitless minutes. (This has been invariably the
outcome of all my attempts at finding my way through the Python C
source.)
I guess the take-home message is that frozenset is a more general
way to canonicalize an iterable object than sorting, even though
the reasons for this still remain a mystery to me... Then again,
just looking at the voodoo that goes into algorithms for computing
hashes fills me with despair. As much as I dislike it, sooner or
later I'll have to go on faith.
Computing the hash value of a container object usually involves
accumulating the hash values of its components, i.e. something like
def hash(container):
hashval = initial_value
for x in container:
hashval = f(hashval, hash(x))
return hashval
Now if one chooses f such that:
* f(x, y) == f(y, x)
* f(x, f(y, z)) = f(f(x, y), z)
(IOW, f defines a commutative and associative operation)
Then it doesn't matter in what order the elements of container are
enumerated, the resulting hash value will always be the same. This
avoids having to find a canonical order to iterate over then elements
in.
--
Arnaud
--
http://mail.python.org/mailman/listinfo/python-list
Re: Many newbie questions regarding python
On Thu, 7 Oct 2010 18:34:58 -0700 (PDT) alex23 wuwe...@gmail.com wrote: On Oct 8, 10:27 am, Steven D'Aprano st...@remove-this- cybersource.com.au wrote: v = [0 for i in range(20)] Absolutely not. Such a code snippet is very common, in fact I've done it myself, but it is a hammer solution -- to a small boy with a hammer, everything looks like a nail that needs hammering. Writing such a list comprehension is a list comp solution. v = [0] * 20 Yes, this is the solution. But the list comp version will work as expected for mutable types, whereas the 'solution' only works for immutable types. If anything, I feel like the list comp version is the correct solution because of its reliability, whereas the multiplication form feels like either a lucky naive approach or relies on the reader to know the type of the initialising value and its mutability. The correct solution is the one that works the way you want it to work (that's my definition, anyway). There is nothing lucky about building a list via [value]*count. It repeats (but not so much duplicates!) value count times. It is well defined (and, I think, justified) behavior. It ceases to be as useful when mutable types are involved, but so what? Use something else, then. And I think it is not too much to ask of a reader of Python to know that integers are immutable. There are enough pitfalls that make this knowledge rather important to have. (I'm actually not convinced that this works as an argument, but there you go.) TL;DR: Don't say correct, say appropriate. /W -- To reach me via email, replace INVALID with the country code of my home country. But if you spam me, I'll be one sour Kraut. -- http://mail.python.org/mailman/listinfo/python-list
how to handle network failures
hi I am trying to write a DataGrabber which reads some data from given url..I made DataGrabber as a Thread and want to wait for some interval of time in case there is a network failure that prevents read(). I am not very sure how to implement this class DataGrabber(threading.Thread): def __init__(self,url): threading.Thread.__init__(self) self.url=url def run(self): data=self.get_page_data() process_data(data) def get_page_data(): try: f=urllib.urlopen(self.url) data=f.read(1024) except IOError: #wait for some time and try again time.sleep(120) data=self.get_page_data() return data Is this the way to implement the part where the thread waits and reads the data again? Will this handle network failures?Can somebody please help? thanks harry -- http://mail.python.org/mailman/listinfo/python-list
Re: Ordering tests in a testsuite
But sometimes you just wanna do it the way you wanna do it. If you name your tests like 'test_01_yadda' and test_02_whatever', then they will be run in the order you want, as given by the numbers. -- http://mail.python.org/mailman/listinfo/python-list
Re: open file on mac
On Fri, 8 Oct 2010 07:16:13 -0700 (PDT) tinauser tinau...@libero.it wrote: on mac I get an error if i do not give the full path of initfile.py (commented out in the code above); on windows i did not have this problem. Am I missing anything? open(initfile.py) opens initfile.py in the current working directory (if you don't do anything funny, that's location where the interpreter is started up in). I assume that you somehow start your interpreter somewhere different on your Mac. But that's just a guess. I don't know enough about Macs and your environment(s) to say for sure. /W -- To reach me via email, replace INVALID with the country code of my home country. But if you spam me, I'll be one sour Kraut. -- http://mail.python.org/mailman/listinfo/python-list
Re: open file on mac
On 10/8/2010 7:16 AM tinauser said... hi, sorry if it is a stupid qustio,but i cannot figure out where's the problem. i've a simpleModule: class Starter: def init(self,num): print hithere! print the answer is ,num import sys,os print path:,sys.path try: #f = open(/Users/lguerrasio/myfold/initfile.py,'r') f = open(initfile.py,'r') f.close() print huurray! except IOError: print The file does not exist, exiting gracefully print This line will always print The module is located in the same folder of initfile.py now,from terminal Only guessing here, but try launching python after you cd to the folder containing initfile.py, then start python ... I import sys and add to the path the folder /Users/ lguerrasio/myfold; the I import the module and execute simpleModule.Starter().init(48) on mac I get an error if i do not give the full path of initfile.py (commented out in the code above); on windows i did not have this problem. Am I missing anything? -- http://mail.python.org/mailman/listinfo/python-list
Re: harmful str(bytes)
Steven D'Aprano writes: On Fri, 08 Oct 2010 15:31:27 +0200, Hallvard B Furuseth wrote: That's not the point - the point is that for 2.* code which _uses_ str vs unicode, the equivalent 3.* code uses str vs bytes. Yet not the same way - a 2.* 'str' will sometimes be 3.* bytes, sometime str. So upgraded old code will have to expect both str and bytes. I'm sorry, this makes no sense to me. I've read it repeatedly, and I still don't understand what you're trying to say. OK, here is a simplified example after 2to3: try:from urlparse import urlparse, urlunparse # Python 2.6 except: from urllib.parse import urlparse, urlunparse # Python 3.2a foo, bar = b/foo, bbar # Data from network, bar normally empty # Statement inserted for 2.3 when urlparse below said TypeError if isinstance(foo, bytes): foo = foo.decode(ASCII) p = list(urlparse(foo)) if bar: p[3] = bar print(urlunparse(p)) 2.6 prints /foo;bar, 3.2a prints /foo;b'bar' You have a module which receives some strings/bytes, maybe data which originates on the net or in a database. The module _and its callers_ may date back to before the 'bytes' type, maybe before 'unicode'. The module is supposed to work with this data and produce some 'str's or bytes to output. _Not_ a Python representation like b'bar'. The module doesn't always know which input is 'bytes' and which is 'str'. Or the callers don't know what it expects, or haven't kept track. Maybe the input originated as bytes and were converted to str at some point, maybe not. Look at urrlib.parse.py and its isinstance(data, str or bytes) calls. urlencode() looks particularly gross, though that one has code which could be factored out. They didn't catch everything either, I posted this when a 2to3'ed module of mine produced URLs with b'bar'. In the pre-'unicode type' Python (was that early Python 2, or should I have said Python 1?) that was a non-issue - it Just Worked, sans possible charset issues. In Python 2 with unicode, the module would get it right or raise an exception. Which helps the programmer fix any charset issues. In Python 3, the module does not raise an exception, it produces b'bar' when it was supposed to produce bar. In 2.*, str-unicode conversion failed or produced the equivalent character/byte data. Yes, there could be charset problems if the defaults were set up wrong, but that's a smaller problem than in 3.*. In 3.*, the bytes-str conversion always _silently_ produces garbage. So you say, but I don't see it. Why is this garbage? To the user of the module, stuff with Python syntax is garbage. It was supposed to be text/string data. b = b'abc\xff' str(b) b'abc\\xff' That's what I would expect from the str() function called with a bytes argument. Since decoding bytes requires a codec, which you haven't given, it can only return a string representation of the bytes. If you want to decode bytes into a string, you need to specify a codec: Except I didn't intend to decode anything - I just intended to output the contents of the string - which was stored in a 'bytes' object. But __str__ got called because a lot of code does that. It wasn't even my code which did it. There's often no obvious place to decide when to consider a stream of data as raw bytes and when to consider it text, and no obvious time to convert between bytes and str. When writing a program, one simply has to decide. Such as network data (bytes) vs urllib URLs (str) in my program. And the decision is different from what one would decide for when to use str and when to use unicode in Python 2. In this case I'll bugreport urlunparse to python.org, but there'll be a _lot_ of such code around. And without an Exception getting raised, it'll take time to find it. So it looks like it'll be a long time before I dare entrust my data to Python 3, except maybe with modules written from scratch. -- Hallvard -- http://mail.python.org/mailman/listinfo/python-list
Re: open file on mac
On Fri, Oct 8, 2010 at 10:16 AM, tinauser tinau...@libero.it wrote:
hi, sorry if it is a stupid qustio,but i cannot figure out where's the
problem.
i've a simpleModule:
class Starter:
def init(self,num):
If you want this to execute upon declaring an instance of Starter, rename
this as __init__.
print hithere!
print the answer is ,num
import sys,os
print path:,sys.path
try:
#f = open(/Users/lguerrasio/myfold/initfile.py,'r')
Try this instead: f = open(os.path.combine('/Users/lguerrasio/myfold',
'initfile.py'),'r')
f = open(initfile.py,'r')
f.close()
print huurray!
except IOError:
print The file does not exist, exiting gracefully
print This line will always print
The module is located in the same folder of initfile.py
now,from terminal I import sys and add to the path the folder /Users/
lguerrasio/myfold; the I import the module and execute
simpleModule.Starter().init(48)
If you had renamed the function __init__ above, all you would have to do is:
instance_of_starter = Starter(48)
Which makes more sense IMO.
Good luck!
Jason
on mac I get an error if i do not give the full path of initfile.py
(commented out in the code above);
on windows i did not have this problem.
Am I missing anything?
--
http://mail.python.org/mailman/listinfo/python-list
--
Jason M. Swails
Quantum Theory Project,
University of Florida
Ph.D. Graduate Student
352-392-4032
--
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Re: SysLogHandler message formatting
On Oct 7, 6:18 am, Vinay Sajip vinay_sa...@yahoo.co.uk wrote: Thanks for the detailed report. I tried posting a response a couple of times, but Google appears to have swallowed it ... trying again. Sorry if it results in multiple responses. Hmm, I too seem to be experiencing this problem... The SysLogHandler aims to work within RFC 5424, though that does provide for some flexibility in message formats. The SysLogHandler sends priorityformatted message, as you've observed, with the formatted message part encoded in UTF-8 with a prepended BOM if it's Unicode. I started to read RFC 5424 yesterday before posting this, but it seemed to describe a much more complex message format than SysLogHandler was producing, so I wasn't sure if that was the reference or not. I may go back and read it completely, now that I know, though. The existing SysLogHandler code seems to work OK with syslog, syslog-ng and rsyslog I agree with this, so I would normally assume that Metalog is the problem and simply stop using it. Unfortunately, I have several systems that use Metalog, and I don't want to introduce any inconsistencies by having one use something else. Switching them all would also be a hassle. - perhaps these are more forgiving than Metalog in the way they parse messages, or perhaps it's a Metalog configuration issue. I'd try posting this issue to the Metalog forum / mailing list to see what feedback they can give. I will do that; I just wanted to see what the Python stance was first. I will keep you apprised of anything determined through that route. If you do think it's a bug in SysLogHandler then please create an issue on bugs.python.org and assign it to me, so I can take a look at it After I communicate with the Metalog community, I will definitely file an issue if necessary. I didn't want to jump the gun, though. I think using an appropriate Formatter will ensure interoperability in any particular scenario. I don't especially want to hard-code any format into SysLogHandler, since a Formatter can be used to set the format flexibly. I think the only problem with doing it that way is that I wasn't initially aware that using a Formatter affected how the message is sent to Syslog, but assumed it only modified the visible portion. I will admit that, until yesterday, I knew nothing of the syslog protocol. Perhaps the best solution would be to simply document the fact that adjusting the message format can affect how the message is parsed by the syslog daemon receiving it. Thank you for your feedback. -- http://mail.python.org/mailman/listinfo/python-list
Re: open file on mac
On Fri, Oct 8, 2010 at 3:39 PM, Jason Swails jason.swa...@gmail.com wrote:
On Fri, Oct 8, 2010 at 10:16 AM, tinauser tinau...@libero.it wrote:
hi, sorry if it is a stupid qustio,but i cannot figure out where's the
problem.
i've a simpleModule:
class Starter:
def init(self,num):
If you want this to execute upon declaring an instance of Starter, rename
this as __init__.
print hithere!
print the answer is ,num
import sys,os
print path:,sys.path
try:
#f = open(/Users/lguerrasio/myfold/initfile.py,'r')
Try this instead: f = open(os.path.combine('/Users/lguerrasio/myfold',
'initfile.py'),'r')
Gah, stupid. os.path.join, not os.path.combine. I'm down for the golf
thing...
f = open(initfile.py,'r')
f.close()
print huurray!
except IOError:
print The file does not exist, exiting gracefully
print This line will always print
The module is located in the same folder of initfile.py
now,from terminal I import sys and add to the path the folder /Users/
lguerrasio/myfold; the I import the module and execute
simpleModule.Starter().init(48)
If you had renamed the function __init__ above, all you would have to do
is:
instance_of_starter = Starter(48)
Which makes more sense IMO.
Good luck!
Jason
on mac I get an error if i do not give the full path of initfile.py
(commented out in the code above);
on windows i did not have this problem.
Am I missing anything?
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Jason M. Swails
Quantum Theory Project,
University of Florida
Ph.D. Graduate Student
352-392-4032
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Quantum Theory Project,
University of Florida
Ph.D. Graduate Student
352-392-4032
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question about a program
question about an assignment: places(home sweet home is here,' ') [4, 10, 15, 18] this is my code: def places(x, y): return [x.index(y) for v in x if (v == y)] so far I'm only getting [4, 4, 4, 4] so the first value is correct, it is just not iterating on to the next three items it needs to -- http://mail.python.org/mailman/listinfo/python-list
Re: Many newbie questions regarding python
On Oct 7, 4:10 pm, Rogério Brito rbr...@ime.usp.br wrote:
[snip]
v = [0 for i in range(20)]
v = [0] * 20
v = []
for i in range(20): v.append(0)
What should I prefer? Any other alternative?
The Pythonic way is to not to preinitialize the list at all. Don't
put anything in the list until you have the data you need.
If possible, I would like to simply declare the list and fill it latter in my
program, as lazily as possible (this happens notoriously when one is using a
technique of programming called dynamic programming where initializing all
positions of a table may take too much time in comparison to the filling of
the
array).
So, if I understand you, you are thinking of your list as a table with
dynamically calculated entries, and want to calculate the entries upon
request.
Three possibilities:
1. Initialize the list using v = [None]*n (I recomment using None
instead of 0 for this, in most cases)
2. Use a dict instead. Dict items pop into existence if you assign
with a key that doesn't exist.
v = {}
Then you can do
v[1] = a
v[10] = n
v[999] = c
3. Consider numpy, which allows preallocation of lists:
v = np.zeros(100)
[snip]
For instance, if I
define:
class C:
f = 1
def g(self):
return f
I get an annoying message when I try to call the g method in an object of type
C, telling me that there's no global symbol called f. If I make g return
self.f
instead, things work as expected, but the code loses some readability.
Is there any way around this or is that simply a matter of life?
Matter of life. It's that way by design.
Carl Banks
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Re: question about a program
On Thu, 7 Oct 2010 17:39:51 -0700 (PDT) Logan Butler killable1...@gmail.com wrote: question about an assignment: places(home sweet home is here,' ') [4, 10, 15, 18] this is my code: def places(x, y): return [x.index(y) for v in x if (v == y)] so far I'm only getting [4, 4, 4, 4] so the first value is correct, it is just not iterating on to the next three items it needs to http://docs.python.org/tutorial/datastructures.html list.index(x) Return the index in the list of the first item whose value is x. It is an error if there is no such item. /W -- To reach me via email, replace INVALID with the country code of my home country. But if you spam me, I'll be one sour Kraut. -- http://mail.python.org/mailman/listinfo/python-list
Re: [Python-ideas] [Python-Dev] Inclusive Range
On Fri, Oct 8, 2010 at 1:26 PM, Steven D'Aprano st...@remove-this-cybersource.com.au wrote: On Fri, 08 Oct 2010 10:21:16 +0200, Antoon Pardon wrote: Personnaly I find it horrible that in the following expression: L[a:b:-1], it is impossible to give a numeric value to b, that will include L[0] into the reversed slice. L = [1, 2, 3, 4, 5] L[5:-6:-1] [5, 4, 3, 2, 1] a = [1, 2, 3, 4, 5, 6] a[::-1] [6, 5, 4, 3, 2, 1] -- Jed Smith j...@jedsmith.org -- http://mail.python.org/mailman/listinfo/python-list
Re: question about a program
On Oct 8, 1:39 am, Logan Butler killable1...@gmail.com wrote: question about an assignment: places(home sweet home is here,' ') [4, 10, 15, 18] this is my code: def places(x, y): return [x.index(y) for v in x if (v == y)] so far I'm only getting [4, 4, 4, 4] so the first value is correct, it is just not iterating on to the next three items it needs to Try this instead: def places(x, y): return [i for i, v in enumerate(x) if v == y] -- http://mail.python.org/mailman/listinfo/python-list
Re: Opening a webpage in the background via webbrowser.open()
2010/10/7 pyt...@bdurham.com: Python 2.7 (32-bit/Windows): Is there a way to use webbrowser.open() to open a web page in the default browser, but in the background, so that the application making the webbrowser.open() call remains the active application? Thank you, Malcolm -- http://mail.python.org/mailman/listinfo/python-list It seems, there might not be a straightforward way for doing this. As you probably found out, webbrowser.open has a parameter autoraise just for specifying this behaviour: webbrowser.open(url[, new=0[, autoraise=True]]) however, the sidenote in the docs also seems to apply: If autoraise is True, the window is raised if possible (note that under many window managers this will occur regardless of the setting of this variable). http://docs.python.org/library/webbrowser.html#webbrowser.open For me (win XP, python 2.5.4) the browser window is always raised after this call, regardless the autoraise option. Possibly, if you are using a gui app, the focus can be maintained form there, in order to avoid activating the browser, otherwise it might be more complicated. (maybe the pywin package might have some means for achieving this?) vbr -- http://mail.python.org/mailman/listinfo/python-list
Re: [Python-ideas] [Python-Dev] Inclusive Range
Jed Smith j...@jedsmith.org writes: a = [1, 2, 3, 4, 5, 6] a[::-1] [6, 5, 4, 3, 2, 1] Nice. Is there a trick to get a -0 index too? Other than doing 'i or len(L)' instead of 'i', that is. L = [1,2,3,4,5] L[2:-2], L[2:-1], L[2:-0] # not quite right:-) ([3], [3, 4], []) -- Hallvard -- http://mail.python.org/mailman/listinfo/python-list
Re: [Python-ideas] [Python-Dev] Inclusive Range
Jed Smith j...@jedsmith.org writes: On Fri, Oct 8, 2010 at 1:26 PM, Steven D'Aprano st...@remove-this-cybersource.com.au wrote: On Fri, 08 Oct 2010 10:21:16 +0200, Antoon Pardon wrote: Personnaly I find it horrible that in the following expression: L[a:b:-1], it is impossible to give a numeric value to b, that will include L[0] into the reversed slice. ^^ L = [1, 2, 3, 4, 5] L[5:-6:-1] [5, 4, 3, 2, 1] a = [1, 2, 3, 4, 5, 6] a[::-1] [6, 5, 4, 3, 2, 1] b doesn't have a numeric value though. -- Arnaud -- http://mail.python.org/mailman/listinfo/python-list
Re: [Python-ideas] [Python-Dev] Inclusive Range
Hallvard B Furuseth h.b.furus...@usit.uio.no writes: Jed Smith j...@jedsmith.org writes: a = [1, 2, 3, 4, 5, 6] a[::-1] [6, 5, 4, 3, 2, 1] Nice. Is there a trick to get a -0 index too? Other than doing 'i or len(L)' instead of 'i', that is. L = [1,2,3,4,5] L[2:-2], L[2:-1], L[2:-0] # not quite right:-) ([3], [3, 4], []) 'i or None' -- Arnaud -- http://mail.python.org/mailman/listinfo/python-list
Re: open file on mac
On Fri, Oct 8, 2010 at 10:41 AM, tinauser tinau...@libero.it wrote: hallo, i'm sorry if the question is very stupid, but i cannot understand what i'm doing wrong here. i have this myModule.py code class Starter: def init(self,num): print hithere! print the answer is ,num import sys,os print path:,sys.path print bye try: ##f = open(/Users/lguerrasio/_myfold/initfile.py,'r') f = open(initfile.py,'r') f.close() print huurray! except IOError: print The file does not exist, exiting gracefully print This line will always print /code the module is in the same folder of initfile from terminal, i import sys and add to the path /Users/lguerrasio/ _myfold/; then i import the module and call myModule.Starter().init(9) now,the file will be opened only if i give the full path, not if i give only the name of the file, although the folder is in the path. what am I missing? sys.path, unless I've missed something, has nothing to do with *opening* a file. It has to do with importing a python module, so it should have no affect on your ability to simply open a file. On my mac, in the interpreter, running open() on a file in the same directory reported by os.path.abspath(os.path.curdir) succeeds without issue. What you might consider is doing something like open(os.path.join(os.path.dirname(__file__), 'initfile.py') That will insure that it always tries to open the file that's in the same directory as the module trying to open it, assuming that's what you want. If what you want is an import and not an open(), well... let us know :) brian -- http://mail.python.org/mailman/listinfo/python-list -- Brian K. Jones My Blog http://www.protocolostomy.com Follow me http://twitter.com/bkjones -- http://mail.python.org/mailman/listinfo/python-list
Re: harmful str(bytes)
On Fri, 08 Oct 2010 15:45:58 +0200 Hallvard B Furuseth h.b.furus...@usit.uio.no wrote: Antoine Pitrou writes: Hallvard B Furuseth h.b.furus...@usit.uio.no wrote: The offender is bytes.__str__: str(b'foo') == b'foo'. It's often not clear from looking at a piece of code whether some data is treated as strings or bytes, particularly when translating from old code. Which means one cannot see from context if str(s) or %s % s will produce garbage. This probably comes from overuse of str(s) and %s. They can be useful to produce human-readable messages, but you shouldn't have to use them very often. Maybe Python 3 has something better, but they could be hard to avoid in Python 2. And certainly our site has plenty of code using them, whether we should have avoided them or not. It's difficult to answer more precisely without knowing what you're doing precisely. But if you already have str objects, you don't have to call str() or format them using %s, so implicit __str__ calls are avoided. Actually, the implicit contract of __str__ is that it never fails, so that everything can be printed out (for debugging purposes, etc.). Nope: $ python2 -c 'str(u\u1000)' Traceback (most recent call last): [...] $ python2 -c 'unicode(\xA0)' Traceback (most recent call last): Sure, but so what? This mainly shows that unicode support was broken in Python 2, because: 1) it tried to do implicit bytes-unicode coercion by using some process-wide default encoding 2) some unicode objects didn't have a succesful str() Python 3 fixes both these issues. Fixing 1) means there's no automatic coercion when trying to mix bytes and unicode. Try for example: [Python 2] ua + b u'ab' [Python 3] a + bb Traceback (most recent call last): File stdin, line 1, in module TypeError: Can't convert 'bytes' object to str implicitly And fixing 2) means bytes object get a meaningful str() in all circumstances, which is much better for debug output. If you don't think that 2) is important, then perhaps you don't deal with non-ASCII data a lot. Failure to print out exception messages (or log entries, etc.) containing non-ASCII characters is a big annoyance with Python 2 for many people (including me). In Python 2, these two UnicodeEncodeErrors made our data safe from code which used str and unicode objects without checking too carefully which was which. That's false, since implicit coercion can actually happen everywhere. And it only fails when there's non-ASCII data involved, meaning the unsuspecting Anglo-saxon developer doesn't understand why his/her users complain. Regards Antoine. -- http://mail.python.org/mailman/listinfo/python-list
Re: [Python-ideas] [Python-Dev] Inclusive Range
On 10/8/2010 4:21 AM, Antoon Pardon wrote:
On Wed, Oct 06, 2010 at 05:28:13PM -0400, Terry Reedy wrote:
Strings and tuples are not natural numbers, but do have least
members ('' and ()), so the bottom end had better be closed.
Why?
Because otherwise one can never include the least member in a slice.
The fact that we have a bottom element in the item space,
doesn't imply that the sequence I need is easiest defined by
using an inclusive lower limit. What if I wanted all none-empty
strings/tuples keys in the tree?
Use 'a' as the lower bound, it being the string that follows ''.
But you really seem to be saying is What if I sometimes want the end
points included and sometimes do not? Slice syntax by itself cannot
handle all four cases, only one, one was chosen and that was closed-open.
If you want flexibility, consider the following:
class my_list(list):
def __getitem__(self, key, include_start=True, include_stop=False):
if (isinstance(key,tuple) and len(key)==2 and
isinstance(key[0], slice)
and isinstance(key[1],tuple) and len(key[1])==2):
key, (include_start, include_stop) = key
start,stop,stride = key.indices(len(self))
if include_start == False:
start += 1
if include_stop == True:
stop += 1
key = slice(start,stop,stride)
print(key)
return list.__getitem__(self, key)
ll = my_list(range(10))
print('standard:', ll[2], ll[1:3], ll[1:3,(True,False)])
print('delete start:', ll[1:3,(False,False)])
print('shift:', ll[1:3,(False,True)])
print('extend stop:', ll[1:3,(True,True)])
slice(1, 3, 1)
standard: 2 [1, 2] [1, 2]
slice(2, 3, 1)
delete start: [2]
slice(2, 4, 1)
shift: [2, 3]
slice(1, 4, 1)
extend stop: [1, 2, 3]
Modify to taste ;-)
--
Terry Jan Reedy
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Re: Sys.exit in secondary threads
In article d841072f-5bad-4b2c-ba14-977b77645...@a15g2000yqm.googlegroups.com, Pakal chambon.pas...@gmail.com wrote: I've noticed that there is nothing in python's documentation regarding the use of sys.exit(code) in a non-main thread. As far as I've seen, the behaviour in this case is to simply exit the thread, without caring about the return code. in the main thread however, the return code becomes the official return code of the whole process. Is that all we have to say about sys.exit() in a multithreaded program ? Or are there corner cases I've missed ? We'd better document this anyway. There is this item among the Caveats for the _thread module in Py3 (thread in Py2): Calling sys.exit() or raising the SystemExit exception is equivalent to calling _thread.exit(). http://docs.python.org/py3k/library/_thread.html http://docs.python.org/library/thread.html It seems like it should be mentioned elsewhere, too, like in sys.exit() itself. Doc patches would be welcomed, I'm sure. -- Ned Deily, n...@acm.org -- http://mail.python.org/mailman/listinfo/python-list
Re: if the else short form
NevilleDNZ neville...@gmail.com wrote in message
news:ad9841df-49a1-4c1b-95d0-e76b72df6...@w9g2000prc.googlegroups.com...
On Oct 7, 9:23 am, Lawrence D'Oliveiro l...@geek-
central.gen.new_zealand wrote:
x = {1 : One, 2 : Two, 3 : Three}.get(i, None Of The Above)
More like:
x = {1:lambda:One, 2:lambda:Two, 3:lambda:Three}.get(i,
lambda:None Of The Above)()
i.e. deferred evaluation of selected case.
In Algol68 this would be:
x:=(i|One,Two,Three|None Of The Above)
The point is, the construction works well when the syntax fully supports it.
When it needs the extra clutter that Python demands, it might not be so
worthwhile. Especially as it's not clear whether, even with lambdas, an
entire dictionary needs to be constructed before a selection can be made. In
fact a brief test showed an list+if (or is it tuple? I can never remember)
construction was much faster and much cleaner:
x = (One,Two,Three)[i-1] if 1=i=3 else Other
NevilleDNZ neville...@gmail.com wrote:
BartC b...@freeuk.com wrote:
Probably there are workarounds here too, but I suspect the syntax won't
be
quite as pert as the Algol68-style example:
x = (i | Zero, One, Two | None of the above) # 0-based
/* ¢ Algol68 case clause is 1-based. ¢ */
Yes, but my example was in Algol68-*style*: 0-based pseudo-syntax just in
case the Pythonians here couldn't get their heads around 1-based indexing..
(I've borrowed a lot from Algol68 when I've needed to design language syntax
(naturally, just the best bits), and I do normally use 1-based.)
--
Bartc
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Re: question about a program
On Thu, Oct 7, 2010 at 5:39 PM, Logan Butler killable1...@gmail.com wrote: question about an assignment: places(home sweet home is here,' ') [4, 10, 15, 18] this is my code: def places(x, y): return [x.index(y) for v in x if (v == y)] so far I'm only getting [4, 4, 4, 4] so the first value is correct, it is just not iterating on to the next three items it needs to Your loop variable is v, but your expression `x.index(y)` does not use v at all, and hence its value is invariant over the course of the loop. Cheers, Chris -- http://blog.rebertia.com -- http://mail.python.org/mailman/listinfo/python-list
Unicode Decode Error
UnicodeDecodeError: 'ascii' codec can't decode byte 0x92 in position 152: ordinal not in range(128). Can someone please help me with this error The error occurs in line wbk.save(p4_merge.xls). I have used import xlwt..Can someone just tell what do I need to do to get rid of this error. I read other forums which explain the error but do not solve it. Thanks in advance.. -- http://mail.python.org/mailman/listinfo/python-list
Re: harmful str(bytes)
On 10/8/2010 9:45 AM, Hallvard B Furuseth wrote: Actually, the implicit contract of __str__ is that it never fails, so that everything can be printed out (for debugging purposes, etc.). Nope: $ python2 -c 'str(u\u1000)' Traceback (most recent call last): File string, line 1, in ? UnicodeEncodeError: 'ascii' codec can't encode character u'\u1000' in position 0: ordinal not in range(128) This could be considered a design bug due to 'str' being used both to produce readable string representations of objects (perhaps one that could be eval'ed) and to convert unicode objects to equivalent string objects. which is not the same operation! The above really should have produced '\u1000'! (the equivavlent of what str(bytes) does today). The 'conversion to equivalent str object' option should have required an explicit encoding arg rather than defaulting to the ascii codec. This mistake has been corrected in 3.x, so Yep. And the equivalent: $ python2 -c 'unicode(\xA0)' Traceback (most recent call last): File string, line 1, in ? UnicodeDecodeError: 'ascii' codec can't decode byte 0xa0 in position 0: ordinal not in range(128) This is an application bug: either bad string or missing decoding arg. In Python 2, these two UnicodeEncodeErrors made our data safe from code which used str and unicode objects without checking too carefully which was which. Code which sort the types out carefully enough would fail. In Python 3, that safety only exists for bytes(str), not str(bytes). If you prefer the buggy 2.x design (and there are *many* tracker bug reports that were fixed by the 3.x change), stick with it. -- Terry Jan Reedy -- http://mail.python.org/mailman/listinfo/python-list
Re: harmful str(bytes)
On 10/8/2010 9:31 AM, Hallvard B Furuseth wrote: That's not the point - the point is that for 2.* code which _uses_ str vs unicode, the equivalent 3.* code uses str vs bytes. Yet not the same way - a 2.* 'str' will sometimes be 3.* bytes, sometime str. So upgraded old code will have to expect both str and bytes. If you want to interconvert code between 2.6/7 and 3.x, use unicode and bytes in the 2.x code. Bytes was added to 2.6/7 as a synonym for str explicitly and only for conversion purposes. -- Terry Jan Reedy -- http://mail.python.org/mailman/listinfo/python-list
script in Linux vs Windows
Hi all, Unsure how to deal with what appears to be \n vs \r issues. The following code works in Linux; o = open(axenfs.reg) n = open(axenfs2.reg, a) while 1: line = o.readline() if not line: break line = line.replace(dword:0,dword:044e) n.write(line) n.close() But in Windows, its one continues line with a bunch of squares in it. So I add + '\r\n' to my second to last line so it looks like; n.write(line + '\r\n') But I still get one continuous line with squares in it. Any ideas? I've been googing all day to no avail. Desperately seeking advice. - aurf -- http://mail.python.org/mailman/listinfo/python-list
Re: Simple database explorer
On Fri, 08 Oct 2010 02:04:39 -0700, dusans wrote: On Oct 7, 7:49 am, Lawrence D'Oliveiro l...@geek- central.gen.new_zealand wrote: In message 21c99273-ed58-4f93-b98a-d9292de5d...@k10g2000yqa.googlegroups.com, dusans wrote: - all the others having ODBC drivers... ODBC seems to be something you use when you can’t use a proper database driver. Its the right answer for a program that needs to be used with many different RDBMSes, especially if you use its metadata access procedures. yes. first i have been mixing native and odbc drivers. Now i only use odbc. Odbc is not the best but its good enought for a sql explorer. Dont know how its on unix thou Use unixODBC. Its a wrapper that lets Windows ODBC drivers be run on UNIX/ Linux and there's a Python module that provides an interface to unixODBC and a Data Manager utility that configures ODBC data sources. The documentation for the module is poor but the module and utility both work well once you've figured out how to use them. -- martin@ | Martin Gregorie gregorie. | Essex, UK org | -- http://mail.python.org/mailman/listinfo/python-list
Re: [Python-Dev] Inclusive Range
On Oct 8, 3:05 pm, Terry Reedy tjre...@udel.edu wrote: doesn't imply that the sequence I need is easiest defined by using aninclusivelower limit. What if I wanted all none-empty strings/tuples keys in the tree? Use 'a' as the lower bound, it being the string that follows ''. No, that would be '\0'. Ian -- http://mail.python.org/mailman/listinfo/python-list
Re: Unicode Decode Error
On Fri, Oct 8, 2010 at 2:31 PM, Pratik Khemka pratikkhe...@hotmail.com wrote: UnicodeDecodeError: 'ascii' codec can't decode byte 0x92 in position 152: ordinal not in range(128). Can someone please help me with this error The error occurs in line wbk.save(p4_merge.xls). I have used import xlwt..Can someone just tell what do I need to do to get rid of this error. I read other forums which explain the error but do not solve it. (1) Always include the *full* exception Traceback. (2) Check whether your version of xlwt is up-to-date. (3) You might have more luck asking on xlwt's newsgroup: http://groups.google.com/group/python-excel Cheers, Chris -- http://mail.python.org/mailman/listinfo/python-list
Re: Unicode Decode Error
On Fri, Oct 8, 2010 at 3:31 PM, Pratik Khemka pratikkhe...@hotmail.comwrote:
*UnicodeDecodeError: 'ascii' codec can't decode byte 0x92 in position
152: ordinal not in range(128)*. Can someone please help me with this
error
The error occurs in line *wbk.save(p4_merge.xls)*. I have used *
import xlwt*..Can someone just tell what do I need to do to get rid of
this error. I read other forums which explain the error but do not solve it.
Thanks in advance..
You're writing non-ascii data to the workbook, which is then trying to
decode it using the default ascii encoding, which will fail. When you
create the workbook, you need to specify the correct encoding, e.g.:
wbk = xlwt.Workbook('utf-8')
or whatever encoding you're actually using.
Cheers,
Ian
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script in Linux vs Windows
Hi all, Unsure how to deal with what appears to be \n vs \r issues. The following code works in Linux; o = open(axenfs.reg) n = open(axenfs2.reg, a) while 1: line = o.readline() if not line: break line = line.replace(dword:0,dword:044e) n.write(line) n.close() But in Windows, its one continues line with a bunch of squares in it. So I add + '\r\n' to my second to last line so it looks like; n.write(line + '\r\n') But I still get one continuous line with squares in it. Any ideas? I've been googing all day to no avail. Desperately seeking advice. - aurf -- http://mail.python.org/mailman/listinfo/python-list
Re: question about a program
On Fri, 8 Oct 2010 14:34:21 -0700 Chris Rebert c...@rebertia.com wrote: On Thu, Oct 7, 2010 at 5:39 PM, Logan Butler killable1...@gmail.com wrote: question about an assignment: places(home sweet home is here,' ') [4, 10, 15, 18] this is my code: def places(x, y): return [x.index(y) for v in x if (v == y)] so far I'm only getting [4, 4, 4, 4] so the first value is correct, it is just not iterating on to the next three items it needs to Your loop variable is v, but your expression `x.index(y)` does not use v at all, and hence its value is invariant over the course of the loop. Nice catch, but the if (v==y) clause nullifies that in any case. The real reason is that list.index(x) returns the index of the *first* occurrence of x, so its invariant by default. /W -- To reach me via email, replace INVALID with the country code of my home country. But if you spam me, I'll be one sour Kraut. -- http://mail.python.org/mailman/listinfo/python-list
Re: script in Linux vs Windows
On Fri, Oct 8, 2010 at 3:52 PM, aurfal...@gmail.com wrote: Hi all, Unsure how to deal with what appears to be \n vs \r issues. The following code works in Linux; o = open(axenfs.reg) n = open(axenfs2.reg, a) while 1: line = o.readline() if not line: break line = line.replace(dword:0,dword:044e) n.write(line) n.close() But in Windows, its one continues line with a bunch of squares in it. So I add + '\r\n' to my second to last line so it looks like; n.write(line + '\r\n') But I still get one continuous line with squares in it. Any ideas? I've been googing all day to no avail. Is the input file formatted the same way? I would guess that the readline call is reading the input file as one continuous line, so that the loop body only runs once, and the '\r\n' only gets added to the very end of the file. The simplest way to deal with this type of issue is to convert the file line endings as needed using dos2unix and unix2dos. -- http://mail.python.org/mailman/listinfo/python-list
Re: Opening a webpage in the background via webbrowser.open()
On 10/08/10 15:11, Vlastimil Brom wrote: webbrowser.open(url[, new=0[, autoraise=True]]) however, the sidenote in the docs also seems to apply: If autoraise is True, the window is raised if possible (note that under many window managers this will occur regardless of the setting of this variable). http://docs.python.org/library/webbrowser.html#webbrowser.open For me (win XP, python 2.5.4) the browser window is always raised after this call, regardless the autoraise option. And with my configuration (Linux, fluxbox) of the browser full-screen on one virtual desktop and usually working in other desktops, this almost *never* happens to me, regardless of the auto-raise option :) -tkc -- http://mail.python.org/mailman/listinfo/python-list
Re: Help with sets
Lawrence D'Oliveiro wrote: Did you know that applying the “set” or “frozenset” functions to a dict return a set of its keys? Seems a bit dodgy, somehow. That's just a consequence of the fact that dicts produce their keys when iterated over, and the set constructor iterates over whatever you give it. -- Greg -- http://mail.python.org/mailman/listinfo/python-list
Re: script in Linux vs Windows
On 08/10/2010 22:52, aurfal...@gmail.com wrote: Hi all, Unsure how to deal with what appears to be \n vs \r issues. The following code works in Linux; o = open(axenfs.reg) n = open(axenfs2.reg, a) while 1: line = o.readline() if not line: break line = line.replace(dword:0,dword:044e) n.write(line) n.close() But in Windows, its one continues line with a bunch of squares in it. So I add + '\r\n' to my second to last line so it looks like; n.write(line + '\r\n') But I still get one continuous line with squares in it. Any ideas? I've been googing all day to no avail. Desperately seeking advice. Open the input file in binary mode and print out the repr for a few lines to see what the file encoding and line ending actually is. That always helps me. :-) -- http://mail.python.org/mailman/listinfo/python-list
Re: script in Linux vs Windows
On Oct 8, 2010, at 4:27 PM, Ian Kelly wrote: On Fri, Oct 8, 2010 at 3:52 PM, aurfal...@gmail.com wrote: Hi all, Unsure how to deal with what appears to be \n vs \r issues. The following code works in Linux; o = open(axenfs.reg) n = open(axenfs2.reg, a) while 1: line = o.readline() if not line: break line = line.replace(dword:0,dword:044e) n.write(line) n.close() But in Windows, its one continues line with a bunch of squares in it. So I add + '\r\n' to my second to last line so it looks like; n.write(line + '\r\n') But I still get one continuous line with squares in it. Any ideas? I've been googing all day to no avail. Is the input file formatted the same way? I would guess that the readline call is reading the input file as one continuous line, so that the loop body only runs once, and the '\r\n' only gets added to the very end of the file. Hi Ian, Thanks very much for the reply. It took a very long time to get my approval mail for this list, so in the interum, I fix it this way (in the event other noobs have issues like myself). First, I replaced a with ab as Winblows treats text files diff then Unix. Second, I used variables instead of actual text so dword:0 is really a var named oldhexuid. And dword:044e is really a new var called newhexuid. What I am really doing here is using NFS in 64 bit Windows XP via AxeNFS client which also works in Windows 7. If you are asking why as Windows 7 does have NFS, it does not map UIDs like Windows XP 32 + SFU can do. So basically I load an LDAP plugin for Windows called pGina which is an LDAP client for Windows. Then during login, I NFS mount, scan a Linux passwd file on that NFS mount for the matching UID of the logged in Windows user and mod the reg so that the windows user UID matches the Linux UID. This way when they mod a file/ folder on the NFS mount, its got proper UID/GID values system wide. Its really too bad the Windows 7 doesn't support NFS map files in terms of matching users with UID/GID. And I didn't want to use Samba as I like my OpenLDAP servers clean and tidy. Since the reg value is in hex, I had to convert the decimal value derived from the passwd file to hex via a sysinternals program called hex2dec. Its this value that I use to mod the reg for AxeNFS. This was a royal PITA but my constraints were clear and no flexible. Hope this helps others. - aurf -- http://mail.python.org/mailman/listinfo/python-list
Re: [Python-ideas] [Python-Dev] Inclusive Range
On Fri, 08 Oct 2010 15:53:17 -0400, Jed Smith wrote: On Fri, Oct 8, 2010 at 1:26 PM, Steven D'Aprano st...@remove-this-cybersource.com.au wrote: On Fri, 08 Oct 2010 10:21:16 +0200, Antoon Pardon wrote: Personnaly I find it horrible that in the following expression: L[a:b:-1], it is impossible to give a numeric value to b, that will include L[0] into the reversed slice. L = [1, 2, 3, 4, 5] L[5:-6:-1] [5, 4, 3, 2, 1] a = [1, 2, 3, 4, 5, 6] a[::-1] [6, 5, 4, 3, 2, 1] Well of course that works, that is the standard Python idiom for reversing a sequence. But the point was that Antoon claimed that there is no numeric value for the end position that will include L[0] in the reversed slice. My example shows that this is not correct. -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: [Python-ideas] [Python-Dev] Inclusive Range
On Fri, 08 Oct 2010 22:10:35 +0200, Hallvard B Furuseth wrote: Jed Smith j...@jedsmith.org writes: a = [1, 2, 3, 4, 5, 6] a[::-1] [6, 5, 4, 3, 2, 1] Nice. Is there a trick to get a -0 index too? Other than doing 'i or len(L)' instead of 'i', that is. What exactly are you expecting? I don't understand why you think that L[-0] and L[0] would be different, when -0 == 0. I'm also unsure why you think that there's anything more (too) to get -- the example shown reverses the entire list. Perhaps if you show what result you are expecting, we can show what slice to give to get it. L = [1,2,3,4,5] L[2:-2], L[2:-1], L[2:-0] # not quite right:-) ([3], [3, 4], []) -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: question about a program
On Thu, 07 Oct 2010 17:39:51 -0700, Logan Butler wrote: question about an assignment: places(home sweet home is here,' ') [4, 10, 15, 18] this is my code: def places(x, y): return [x.index(y) for v in x if (v == y)] so far I'm only getting [4, 4, 4, 4] so the first value is correct, it is just not iterating on to the next three items it needs to Not every tool is a hammer, not every list builder needs to be a list comp, and not every function needs to be a one-liner. The simplest way to deal with this is to do an explicit loop. Also, your names x and y are misleading. It is conventional to expect x and y to be numeric values, so it is best to pick more descriptive names. def places(s, sub): Return indexes into string s where non-overlapping copies of substring sub is found, or [-1] if not found at all. n = len(sub) start = 0 indexes = [] try: while True: i = s.index(sub, start) indexes.append(i) start = i + n except ValueError: if not indexes: indexes = [-1] return indexes -- Steven -- http://mail.python.org/mailman/listinfo/python-list
[issue10046] Correction to atexit documentation
Georg Brandl ge...@python.org added the comment: One could also argue that on SIGINT, the program is not killed but interrupted by the signal :) What about ... killed by an unhandled signal ...? -- nosy: +georg.brandl ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue10046 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue10019] json.dumps with indent = 0 not adding newlines
Bob Ippolito b...@redivi.com added the comment: The test in the patch assumes a specific iteration order for the dict h, changing the dict to have only one key would fix this problem with the test. -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue10019 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue10019] json.dumps with indent = 0 not adding newlines
Bob Ippolito b...@redivi.com added the comment: The test also repeats an equivalent dict to h in the check function. -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue10019 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue10019] json.dumps with indent = 0 not adding newlines
Bob Ippolito b...@redivi.com added the comment: I just applied a version of this patch with corrections to the tests here: http://code.google.com/p/simplejson/source/detail?r=234 -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue10019 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue10040] GZipFile failure on large files
Robert Rohde ro...@robertrohde.com added the comment: It's Windows 7 Ultimate (64-bit) on a very high end system. I don't think it would be very practical to distribute a 2 GB test file. Though I might be able to get it to a couple people if someone wanted to really study the issue. Though if it is an integer overflow (or something like that), then I would suspect that GZipFile would show corruption most of the time once the files got large enough. For example, it might occur for all files expanding to larger than 2^32 bytes (4 GB). (That's just speculation, I haven't tested it except to note that it failed the very first time I tried to use a file this large.) Perhaps someone familiar with the code could look for places where integers might overflow? -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue10040 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
