filelike 0.3.0
Hi All, I'm pleased to announce the v0.3.0 release of filelike, a module for easy creation and manipulation of objects that provide a rich file-like interface. New in this version we have: * support for seek() and tell() in FileLikeBase * much better support for intermingling reads and writes * rearranged filelike.wrappers to provide consistent naming scheme * filelike.join function: concatenate several file-like objects so they behave like a single file * filelike.slice function: access a portion of a file-like object as if it were an independent file * Buffered wrapper class: emulate seekability on streaming input/output Along with a host of small fixes and new test cases. All the details are available at the project website: http://www.rfk.id.au/software/projects/filelike/ Cheers, Ryan -- Ryan Kelly http://www.rfk.id.au | This message is digitally signed. Please visit r...@rfk.id.au| http://www.rfk.id.au/ramblings/gpg/ for details signature.asc Description: This is a digitally signed message part -- http://mail.python.org/mailman/listinfo/python-announce-list Support the Python Software Foundation: http://www.python.org/psf/donations.html
Re: Suggested improvements for IDLE (non-official)
Tim H wrote: r wrote: On Jan 14, 4:43 pm, Terry Reedy tjre...@udel.edu wrote: OFF-TOPIC:(but related) What is the state of Tkinter at this point. Is an active effort under way to port TK 8.5 into Python? Tkinter and IDLE are very important to Python, but i understand there are much more important areas where the GURU's are concentrating. Should there be a calling for others to get involved here? I would like to help out. Thanks Maybe I'm misunderstanding something here, but About Idle in Python 2.6.1 (win32) says Tk version: 8.5 Same in 3.0. I check .../python30/tcl/ and it has tck8/ tcl8.5, tix8.4, tk8.5 subdirs. -- http://mail.python.org/mailman/listinfo/python-list
Re: Does Python really follow its philosophy of Readability counts?
Terry Reedy tjre...@udel.edu writes: Have you looked at Tim Sweeney's talk that I mentioned in another post? http://www.st.cs.uni-saarland.de/edu/seminare/2005/advanced-fp/docs/s... I did. He gives a really nice use case for Python's ability to dynamically modify classes imported from a library. (Were not you arguing against that? Or was is someone else?) He is talking about extending classes by something like inheritance, not modifying them dynamically. This is also in the context of an extremely powerful static type system with existential and dependent types, and totality proofs for just about everything. That is about a billion light years away from anything anyone has ever proposed for Python. -- http://mail.python.org/mailman/listinfo/python-list
Re: Alphametric fun with Python
Terry Reedy: It illustrates well the point you intended. I don't know what my point was. A suggestion: with that solver, to find solution in a faster way you have to write many equations. Bye, bearophile -- http://mail.python.org/mailman/listinfo/python-list
Re: Does Python really follow its philosophy of Readability counts?
James Mills prolo...tcircuit.net.au wrote: At the most basic level do you really think a machine really cares about whether -you- the programmer has illegally accessed something you shouldn't have ? Yes it does - this is exactly why some chips have supervisor and user modes - to keep the monkeys away from the typewriter. - Hendrik -- http://mail.python.org/mailman/listinfo/python-list
Re: Convention vs. fascism
Aaron Brady cas@gmail.com wrote: On Jan 15, 6:41 pm, Steven D'Aprano st...@remove-this- cybersource.com.au wrote: On Fri, 16 Jan 2009 10:24:19 +1100, Ben Finney wrote: Steven D'Aprano st...@remove-this-cybersource.com.au writes: On Fri, 16 Jan 2009 07:58:49 +1100, Ben Finney wrote: Steven D'Aprano st...@remove-this-cybersource.com.au writes: On Thu, 15 Jan 2009 10:08:37 +0100, Diez B. Roggisch wrote: Familiarize yourself with PEP8 for naming and coding-conventions first. 8 -- stuff giving Diez a hard time for the above Oh come on you lot - you are carrying on as if Diez were wearing his skull socks again - do me a favour and give him a break! - Hendrik -- http://mail.python.org/mailman/listinfo/python-list
Re: spam on the list - how are things now?
Terry Reedy tjre...@udel.edu wrote: James Mills wrote: On Fri, Jan 16, 2009 at 1:30 PM, s...@pobox.com wrote: We've been running SpamBayes on the news-to-mail gateway on mail.python.org for a couple weeks now. To me it seems like the level of spam leaking onto the list has dropped way down but I'd like some feedback from people who read the python-list@python.org mailing list on the topic. Agreed. It has gone down. Thank you for taking the time to do something about it :) Reading from gmane, there has not been much obvious spam lately. Thanks. I read this solely via the mailing list - and Yes, whatever was done has helped a lot. - Hendrik -- http://mail.python.org/mailman/listinfo/python-list
Re: [Python-Dev] multiprocessing vs. distributed processing
On Fri, Jan 16, 2009 at 6:30 PM, Matthieu Brucher matthieu.bruc...@gmail.com wrote: 2009/1/16 James Mills prolo...@shortcircuit.net.au: I've noticed over the past few weeks lots of questions asked about multi-processing (including myself). Funny, I was going to blog about this, but not just for Python. For those of you new to multi-processing, perhaps this thread may help you. Some things I want to start off with to point out are: multiprocessing will not always help you get things done faster. Of course. There are some programs that are I/O or memory bandwidth bound. So if one of those bottlenecks is common to the cores you use, you can't benefit from their use. be aware of I/O bound applications vs. CPU bound Exactly. We read a lot about fold...@home, s...@home, they can be distributed, as it is more or less take a chunk, process it somewhere and when you're finish tell me if there something interesting in it. Not a lot of communications between the nodes. Then, there are other applications that process a lot of data, they must read data from memory, make one computation, read other data, compute a little bit (finite difference schemes), and here we are memory bandwidth bound, not CPU bound. multiple CPUs (cores) can compute multiple concurrent expressions - not read 2 files concurrently Let's say that this is true for the usual computers. Clusters can make concurrent reads, as long as there is the correct architecture behind. Of course, if you only have one hard disk, you are limited. in some cases, you may be after distributed processing rather than multi or parallel processing Of course. Clusters can be expensive, their interconnections even more. So if your application is made of independent blocks that can run on small nodes, without much I/Os, you can try distributed computing. If you need big nodes with high-speed interconnections, you will have to use parallel processing. This is just what my thoughts on the sucjet are, but I think I'm not far from the truth. Of course, if I'm proved wrong, I'll be glad to hear why. Thank you Matthieu for your response. Very good comments on some of the points I raised. Hopefully those interested in the topic will learn from this thread. cheers James PS: I assumed you meant to post back to the list and not just me :) -- http://mail.python.org/mailman/listinfo/python-list
Re: Convention vs. fascism
On Fri, 16 Jan 2009 10:03:28 +0200, Hendrik van Rooyen wrote: Oh come on you lot - you are carrying on as if Diez were wearing his skull socks again - do me a favour and give him a break! Well, for what it's worth, I should say one final thing: I didn't disagree with what Diez said, only the way he said it. I thought my original post made that clear, but perhaps I should have said so explicitly. And I certainly don't think less of him because of it. And... skull socks? Cool. Where can I get some? -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: reverse dict lookup Relation class
On Jan 14, 7:04 pm, Chris Rebert c...@rebertia.com wrote:
On Wed, Jan 14, 2009 at 4:30 PM, Aaron Brady castiro...@gmail.com wrote:
Hi, this is a continuation of something that comes up now and again
about reverse lookups on dictionaries, as well as a follow-up to my
pursuit of a Relation class from earlier.
snip
Or, and this is the interesting part, use the ('identificationally')
same tuples in both mappings, since the object is only mentioned, not
used.
phone[ '555-963' ]= [ ( 'Joan', '555-963', '9a-5p' ) ]
phone[ '555-964' ]= [ ( 'Joan', '555-964', '5p-11p' ) ]
name[ 'Joan' ]= [ ( 'Joan', '555-963', '9a-5p' ), ( 'Joan', '555-964',
'5p-11p' ) ]
hourstocall[ '9a-5p' ]= [ ( 'Joan', '555-963', '9a-5p' ) ]
hourstocall[ '5p-11p' ]= [ ( 'Joan', '555-964', '5p-11p' ) ]
What's the best way to construct this class? Or, do you have an
argument that it could not be simpler than using a relational db?
Brainstorming, not flamestorming.
Once you get beyond a main dict (e.g. name2phone) and one that's its
inverse (e.g. phone2name), yeah, I'd probably say you should be using
a relational DB for this. You could also use objects, but it sounds
like you really want to use SQL-like querying, which isn't well-suited
to plain objects (though it'd be fine with an ORM).
I want the simplest data structure that can hold a relation. In this
case, I would declare a new record as:
PhoneInfo( 'Joan', '555-963', '9a-5p' )
PhoneInfo( 'Joan', '555-964', '5p-11p' )
However the syntax is flexible, such as in 'PhoneInfo.add' etc.
I can query the structure myself if I can access it as an iterable of
tuples. I think I want to use named tuples.
for rec in PhoneInfo.records:
if rec.name== 'Joan':
something
Or I can just use itertools.ifilter.
recset= ifilter( lambda rec: rec.name== 'Joan', PhoneInfo.records )
for rec in recset:
something
Using objects is one advantage, since they are live (unserialized)
and native, such as a relation of socket connections. (SQL would
require an additional mapping object and a key to accomplish it.)
--
http://mail.python.org/mailman/listinfo/python-list
RE: problem in implementing multiprocessing
I create two heavy objects sequentially without using multipleProcessing then creation of the objects takes 2.5 sec.if i create these two objects in separate process then total time is 6.4 sec. i am thinking it is happening due to the pickling and unpickling of the objects.if i am right then what could be the sollution. my system configuration: dual-core processor winXP python2.6.1 gopal mishra wrote: Hello, I am trying to implement the multiprocessing in my application to take advantage of multiple cores. I have created two Separate process something like this. que = Queue Process(target = getData, args=(que , section, MdbFile,)).start() Process(target = getData, args=(que , section, MdbFile,)).start() In getData function I create the object(max 7MB size) and add in to queue (que.put (object)). After that I fetch the object using que.get () and use in my application. but it takes more time to get the data. More time than what? Than not getting the date? Than getting it some other way? CPU, OS, and Python version may also be relevant. Any one can help me out this problem. Thanks, Sibtey My code from multiprocessing import Process, Queue def getData(queue, section, mdbFile): This function returns the gapappdata for the given mdb file. app = MdbFile(mdbFile) mdbData = app.data#it is a heavy object queue.put((section,mdbData)) def getData2(mdbFile): This function returns the gapappdata for the given mdb file. app = MdbFile(mdbFile) mdbData = app.data#it is a heavy object return mdbData def test_multipleProcess(fromMdbFile, toMdbFile): #multipleProcess t1 = time.time() queue = Queue() sections = ['From', 'To'] Process(target= getData_1, args=(queue, 'From',fromMdbFile,)).start() Process(target= getData_1, args=(queue, 'To',toMdbFile,)).start() section, gapAppData = queue.get() section, gapAppData = queue.get() t2 = time.time() print total time using multiProcessing:,t2-t1 d1 = getData2(fromMdbFile) d2 = getData2(toMdbFile) print total time withought multiProcessing:, time.time()-t2 if __name__=='__main__': f1 =r a.mdb f2 =rb.mdb test_multipleProcess(f1,f2) -- http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
Re: Does Python really follow its philosophy of Readability counts?
Hendrik van Rooyento keep the monkeys away from the typewriter. Love it... just fully describes why we should keep some parts hidden from the pointyHairedBossHired Code monkeys... I'd like to think I know what I am doing... can't say the same of all people that have access to the code unfortunately... also I have very little control over who has access to what.. if pointy haired boss says monkey A has access to all then gotta live with it. So this is why, however shameful it may be, I will not use python here for production stuff. --- God I miss it, however scary the ride may feel to a hardcore Java guy.. it sure was fun. Terry Reedy I did. He gives a really nice use case for Python's ability to dynamically modify classes imported from a library. (Were not you arguing against that? Or was is someone else?) There is a place for these kind of hacks, however, see code monkeys above, I would want to make sure it is very well encapsulated (wrapper library for example) before I release it as a lib to the internal zoo. The thing that gets me with all this talk about dynamic access to private wannabe variables... What happens to your coupling, I like my code nice and tidy, high internal coupling is allowed but from the wild I would tend to want to reduce it as much as possible. Dynamically replaced code is a nice idea indeed and I could think of a few really nice uses for this (good luck for this kind of flexibility in Java) but doing so you willingly break the encapsulation convention, thus you must also manage the possible consequences that arise from this break. Python is nice quick and flexible... but it provides so much rope a monkey would hang the whole ecosystem with it. Me I like the big spool, but as some wise dude once said with great power comes great responsibilities. On Fri, Jan 16, 2009 at 3:53 PM, Hendrik van Rooyen m...@microcorp.co.zawrote: James Mills prolo...tcircuit.net.au wrote: At the most basic level do you really think a machine really cares about whether -you- the programmer has illegally accessed something you shouldn't have ? Yes it does - this is exactly why some chips have supervisor and user modes - to keep the monkeys away from the typewriter. - Hendrik -- http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
Re: reverse dict lookup Relation class
On Jan 14, 7:54 pm, MRAB goo...@mrabarnett.plus.com wrote:
Aaron Brady wrote:
Hi, this is a continuation of something that comes up now and again
about reverse lookups on dictionaries, as well as a follow-up to my
pursuit of a Relation class from earlier.
For a reverse lookup, you just need two lookups.
name= {}
phone= {}
name[ '555-963' ]= 'Joan'
phone[ 'Joan' ]= '555-963'
Though maybe the keys in 'name' should be names, instead of the
values in it. The variable name doesn't clarify that. (What is more
natural to you in reading code? Is one obviously wrong?)
phone[ '555-963' ]= 'Joan'
name[ 'Joan' ]= '555-963'
Consider str(x). It isn't saying x is a string, it's saying x as a
string. Similarly, ord(x) says the ordinal value of x. So,
phone[x] means the phone number of x.
That's true. However, I want to map individual fields of records to
the tuples (named tuples) containing the records themselves (unless I
just need a set of tuples).
I think what you are talking about is accessing the 'phone' field,
which was not what I was thinking. (You see that in algorithm
pseudocode a bit.) For that, you could use 'name[ tuple1 ]' to obtain
the name. However, in relational data, there is no single key, of
which the rest of the fields are just accessories. (Does that make
sense?) I think I want to use the multiple mappings for different
ways to have access to the data.
[snip] What's the best way to construct this class? Or, do you have an
argument that it could not be simpler than using a relational db?
Brainstorming, not flamestorming.
You could imagine an object where you provide a field name and a value
and it returns all those entries where that field contains that value.
That, basically, is a database.
That's true. The mapping objects wouldn't be particularly helpful if
I had patterns to match instead of exact values... as now I'm thinking
you usually would. In other words, providing the mapping objects,
even grouped together in a provider object, would only handle a small
subset of possible queries, specifically exact equality. For example,
the 'hourstocall' object is basically useless as specified. Even
separating the fields wouldn't help in a hash. The separate fields
would need to be stored in sorted lists, using 'bisect' to test
inequality. (How does an SQL service implement inequality checks
anyway?)
However, it's interesting that my first thought was to start out with
a mapping object, instead of just a set of 'namedtuple's.
--
http://mail.python.org/mailman/listinfo/python-list
Re: List comprehension - NameError: name '_[1]' is not defined ?
Terry Reedy wrote:
Peter Otten wrote:
List comprehensions delete the helper variable after completion:
I do not believe they did in 2.4. Not sure of 2.5.
As Mario said, 2.4, 2.5, and 2.6 all show the same behaviour.
There is certainly
a very different implementation in 3.0 and, I think, 2.6. OP
neglected to mention Python version he tested on. Code meant to run on
2.4 to 3.0 cannot depend on subtle listcomp details.
3.0 behaves different. Like generator expressions listcomps no longer leak
the loop variable, and this is implemented by having each listcomp execute
as a nested function:
In 3.0
def f(): [i for i in [1]]
import dis
dis.dis(f)
1 0 LOAD_CONST 1 (code object listcomp at
0x01349BF0, file pyshell#12, line 1)
3 MAKE_FUNCTION0
6 LOAD_CONST 2 (1)
9 BUILD_LIST 1
12 GET_ITER
13 CALL_FUNCTION1
16 POP_TOP
17 LOAD_CONST 0 (None)
20 RETURN_VALUE
This is more robust (at least I can't think of a way to break it like the
2.x approach) but probably slower due to the function call overhead. The
helper variable is still there, but the possibility of a clash with another
helper is gone (disclaimer: I didn't check this in the Python source) so
instead of
# 2.5 and 2.6 (2.4 has the names in a different order)
def f():
... [[i for i in ()] for k in ()]
...
f.func_code.co_varnames
('_[1]', 'k', '_[2]', 'i')
we get
# 3.0
def f():
... [[i for i in ()] for k in ()]
...
f.__code__.co_varnames
()
The variables are gone from f's scope, as 3.x listcomps no longer leak their
loop variables.
f.__code__.co_consts
(None, code object listcomp at 0x2b8d7f6d7530, file stdin, line 2,
())
outer = f.__code__.co_consts[1]
outer.co_varnames
('.0', '_[1]', 'k')
Again the inner listcomp is separated from the outer.
outer.co_consts
(code object listcomp at 0x2b8d7f6d26b0, file stdin, line 2, ())
inner = outer.co_consts[0]
inner.co_varnames
('.0', '_[1]', 'i')
Peter
--
http://mail.python.org/mailman/listinfo/python-list
Re: lazy evaluation is sometimes too lazy... help please.
Ken Pu wrote: Hi, below is the code I thought should create two generates, it[0] = 0,1,2,3,4,5, and it[1] = 0,10,20,30,..., but they turn out to be the same!!! from itertools import * itlist = [0,0] for i in range(2): itlist[i] = (x+(i*10) for x in count()) print what's in the bags: print list(islice(itlist[0], 5)) print list(islice(itlist[1], 5)) The output is: [10, 11, 12, 13, 14] [10, 11, 12, 13, 14] I see what Python is doing -- lazy evaluation doesn't evaluate (x+(i*10) for x in count()) until the end. It doesn't evaluate it until you ask it to, which is the right behavior. However, when evaluated, it evaluates i also, which is the last value to which i was assigned, namely the integer 1. I'm going to get flamed pretty hard for this, but it doesn't seem to be the intuitive behavior to me either. However, in a purely functional language, you wouldn't be able to construct a list of generators in this way. With python, you have to remember to adopt a purely functional design and then pray for best results. You can store generators in a list, but they need to be constructed properly. I can't perfectly transmogrify your code into functional code because I don't think making the particular anonymous generator you want is possible in python. However this is how I would make a close approximation: from itertools import * def make_gen(i): for x in count(): yield x + (i * 10) itlist = [make_gen(i) for i in xrange(2)] print what's in the bags: print list(islice(itlist[0], 5)) print list(islice(itlist[1], 5)) James -- James Stroud UCLA-DOE Institute for Genomics and Proteomics Box 951570 Los Angeles, CA 90095 http://www.jamesstroud.com -- http://mail.python.org/mailman/listinfo/python-list
Re: Possible bug in Tkinter - Python 2.6
On Thu, 15 Jan 2009 19:09:00 +0100, José Matos jaoma...@gmail.com wrote: On Thursday 15 January 2009 15:28:36 r wrote: First of all be very careful using from module import * or you will have name conflicts. Tkinter is made to be imported this way and i do it all the time. for the others do. import tkMessageBox as MB import tkFileDialog as FD or whatever floats your boat. Importing explicitly works for me in Fedora 11 (rawhide): - from Tkinter import * from tkMessageBox import askyesno from tkFileDialog import askopenfilename [snip] What do you mean by 'works'...? You don't have the problem? It doesn't change a thing for me... -- python -c print ''.join([chr(154 - ord(c)) for c in 'U(17zX(%,5.zmz5(17l8(%,5.Z*(93-965$l7+-']) -- http://mail.python.org/mailman/listinfo/python-list
Re: Possible bug in Tkinter - Python 2.6
On Thu, 15 Jan 2009 23:49:22 +0100, Terry Reedy tjre...@udel.edu wrote: Eric Brunel wrote: [snip] And BTW, if this is actually a bug, where can I report it? bugs.python.org Thanks. I reported the problem. -- python -c print ''.join([chr(154 - ord(c)) for c in 'U(17zX(%,5.zmz5(17l8(%,5.Z*(93-965$l7+-']) -- http://mail.python.org/mailman/listinfo/python-list
Re: Client Socket Connection to Java server
On 16 Gen, 08:10, TechieInsights gdoerm...@gmail.com wrote: I am having problems with a socket connection to a Java server. In java I just open the socket, pass the length and then pass the bits across the socket. I created a socket object: import socket class MySocket: def __init__(self, host='localhost', port = 28192, buffsize = 1024): socket.setdefaulttimeout(10) self.host = host self.port = port self.buffsize = buffsize self.socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM) self.socket.connect((host, port)) def send(self, data): self.socket.send(data) def receive(self): return self.socket.recv(self.buffsize) def sendAndReceive(self, data): self.send(data) return self.receive() def close(self): self.socket.close() But the java server gives the error: WARNING: Incoming Message length invalid. Discarding The data is of type string (xml). Am I doing something wrong? I know you have to reverse the bits when communicating from C++ to Java. Could this be the problem? I figured it would not because it said the length was invalid. I just started looking at python sockets tonight... and I don't have a real deep base with socket connections as it is... any help would be greatly appreciated. Greg What is the server protocol? What are you sending? Saying 'xml' is not enough to understand the problem ... byte order could be a problem only if the message include binary representations of 2-bytes or 4-bytes integer. With XML this should not be the case Ciao FB -- http://mail.python.org/mailman/listinfo/python-list
Re: Python 3 isinstance
Carl Banks pavlovevide...@gmail.com wrote:
On Jan 15, 1:08 pm, Duncan Booth duncan.bo...@invalid.invalid wrote:
Carl Banks pavlovevide...@gmail.com wrote:
I don't see what the big deal is. Right now isinstance accepts a
typ
e
or a tuple of types. The code could be changed to allow a type, or
any iterable the returns types (wherein every items of the sequence
is required to be a type). What's messy about that?
No, it isn't restricted to a type or a tuple of types: right now
isinstan
ce
accepts X where X is a type or a tuple of X. The definition is
recursive, and the data structure can be deeply nested, but (because
tuples are immutable) it cannot be infinite.
e.g. isinstance('x', (int, (float, str)),),),),))
True
Oh. Not sure what the use case for THAT was, but that would make
things messy.
Duck typing purism?
If you can use it to specify an exception you want to handle, then you
can put it in a tuple with other exception specifications you can also
handle. If you had to check whether it was a class or tuple to work out
which sort of concatenation to use then you are breaking the first law
of ducks.
I think exception specifications came first and isinstance/issubclass
followed suit, except of course exception specification were more
complex as they could be classes, strings, or tuples of exception
specifications.
That still leaves the question whether anyone has ever actually taken
advantage of this feature. You can do isinstance(x, (IntType, LongType,
StringTypes)) but I didn't even know that StringTypes existed until a
couple of moments ago, and I intend to forget about it again
immediately. Grepping through the Python libraries on my system it looks
like a lot of programmers don't even realise you can combine types into
a tuple.
--
Duncan Booth http://kupuguy.blogspot.com
--
http://mail.python.org/mailman/listinfo/python-list
Re: Alphametric fun with Python
bearophileh...@lycos.com wrote: Terry Reedy: It illustrates well the point you intended. I don't know what my point was. I quoted and was responding to Raymond. A suggestion: with that solver, to find solution in a faster way you have to write many equations. I did... one for each column + plus the implied one that digits represented by the same letter get same value and that those represented by different letters gets different values. -- http://mail.python.org/mailman/listinfo/python-list
Re: lazy evaluation is sometimes too lazy... help please.
James Stroud schrieb: Ken Pu wrote: Hi, below is the code I thought should create two generates, it[0] = 0,1,2,3,4,5, and it[1] = 0,10,20,30,..., but they turn out to be the same!!! from itertools import * itlist = [0,0] for i in range(2): itlist[i] = (x+(i*10) for x in count()) print what's in the bags: print list(islice(itlist[0], 5)) print list(islice(itlist[1], 5)) The output is: [10, 11, 12, 13, 14] [10, 11, 12, 13, 14] I see what Python is doing -- lazy evaluation doesn't evaluate (x+(i*10) for x in count()) until the end. It doesn't evaluate it until you ask it to, which is the right behavior. However, when evaluated, it evaluates i also, which is the last value to which i was assigned, namely the integer 1. I'm going to get flamed pretty hard for this, but it doesn't seem to be the intuitive behavior to me either. However, in a purely functional language, you wouldn't be able to construct a list of generators in this way. With python, you have to remember to adopt a purely functional design and then pray for best results. You can store generators in a list, but they need to be constructed properly. I can't perfectly transmogrify your code into functional code because I don't think making the particular anonymous generator you want is possible in python. However this is how I would make a close approximation: from itertools import * def make_gen(i): for x in count(): yield x + (i * 10) itlist = [make_gen(i) for i in xrange(2)] print what's in the bags: print list(islice(itlist[0], 5)) print list(islice(itlist[1], 5)) James You could just as well use the original expression in make_gen, too: from itertools import * def make_gen(i): return (x + (i*10) for x in count()) itlist = [make_gen(i) for i in xrange(2)] print what's in the bags: print list(islice(itlist[0], 5)) print list(islice(itlist[1], 5)) what's in the bags: [0, 1, 2, 3, 4] [10, 11, 12, 13, 14] -- http://mail.python.org/mailman/listinfo/python-list
Re: English-like Python
On Jan 16, 5:39 pm, Erik Max Francis m...@alcyone.com wrote: Inform 7 has some interesting ideas, but I think the general problem with English-like programming language systems is that once you get into the nitty gritty details, you end up having to know exactly the right things to type, This has always been my impression of Inform 7. I have a lot of respect for what they've set out to achieve but English isn't exactly known for its lack of ambiguity. This is great for literature but not so helpful for programming. which ultimately get just as complicated as a more traditional programming language syntax. And much more verbose, as well. -- http://mail.python.org/mailman/listinfo/python-list
Re: Does Python really follow its philosophy of Readability counts?
Paul Rubin wrote: Terry Reedy tjre...@udel.edu writes: Have you looked at Tim Sweeney's talk that I mentioned in another post? http://www.st.cs.uni-saarland.de/edu/seminare/2005/advanced-fp/docs/s... I did. He gives a really nice use case for Python's ability to dynamically modify classes imported from a library. (Were not you arguing against that? Or was is someone else?) He is talking about extending classes by something like inheritance, not modifying them dynamically. This is also in the context of an extremely powerful static type system with existential and dependent types, and totality proofs for just about everything. That is about a billion light years away from anything anyone has ever proposed for Python. If the library framework were written in Python, one would have a choice between creating a parallel class hierachy (through inheritance) that dupicates *every* class in the original hierachy and dynamically patching just those classes that need to be changed. He only discussed the former option because that was the only one available. If, for instance, one only needed to change the base class, patching just that would be much easier. Hence my comment. tjr -- http://mail.python.org/mailman/listinfo/python-list
PyPlot
Hi , I need Pyplot module , How to get and install ( plug in with my python 2.4 distribution ) !!! TIA. Shah. -- http://mail.python.org/mailman/listinfo/python-list
Problem using python C API
Hi,
I'm trying to use the Python C API but I have
a problem when importing my new module.
Here is my (short) code:
#include Python.h
long sumList(PyObject *list) {
int i, n;
long total = 0;
PyObject *item;
n = PyList_Size(list);
if (n 0) return NULL;
for (i = 0; i n; i++) {
item = PyList_GetItem(list, i);
if (!PyInt_Check(item)) continue;
total += PyInt_AsLong(item);
}
return total;
}
PyObject *wrap_sumList(PyObject *self, PyObject *args) {
PyObject *list;
PyObject *total;
if (!PyArg_ParseTuple(args, 0, list)) {
return NULL;
}
total = Py_BuildValue(l, sumList(list));
return total;
}
static PyMethodDef exampleMethods[] = {
{sumList, wrap_sumList, METH_O},
{NULL}
};
void initexample() {
PyObject *m;
m = Py_InitModule(example, exampleMethods);
}
My compilations lines:
gcc -Wall -fpic -c -I/usr/include/python2.4 -I/usr/lib/python2.4/config
mytest.c
gcc -shared mytest.o -o examplemodule.so
When I try to import examplemodule, I obtain the following message:
import examplemodule
Traceback (most recent call last):
File stdin, line 1, in ?
ImportError: dynamic module does not define init function
(initexamplemodule)
Someone has an idea ?
Thx,
Marc.
--
http://mail.python.org/mailman/listinfo/python-list
Re: Does Python really follow its philosophy of Readability counts?
Terry Reedy tjre...@udel.edu writes: If the library framework were written in Python, one would have a choice between creating a parallel class hierachy (through inheritance) that dupicates *every* class in the original hierachy and dynamically patching just those classes that need to be changed. I think I understand what you're saying, but it could be handled with generics. -- http://mail.python.org/mailman/listinfo/python-list
Re: lazy evaluation is sometimes too lazy... help please.
The minimal correction, I guess, is to write itlist[i] = (x+(i*10) for i in [i] for x in count()) instead of itlist[i] = (x+(i*10) for x in count()) although itlist[i] = (x+(i*10) for i,s in (i,count()) for x in s) will better mimic generalizations in the sense that the minimal correction delays the evaluation of count(), which doesn't matter in the case of count(), but might make a difference if you replace it with some other expression. The point is that the first iterator-producing expression in a generator expression - eg the X in (exp for vars in X...) - is evaluated immediately in the surrounding context, in contrast to the rest of the genexp. Cheers, BB Ken Pu wrote: Hi, below is the code I thought should create two generates, it[0] = 0,1,2,3,4,5, and it[1] = 0,10,20,30,..., but they turn out to be the same!!! from itertools import * itlist = [0,0] for i in range(2): itlist[i] = (x+(i*10) for x in count()) print what's in the bags: print list(islice(itlist[0], 5)) print list(islice(itlist[1], 5)) The output is: [10, 11, 12, 13, 14] [10, 11, 12, 13, 14] I see what Python is doing -- lazy evaluation doesn't evaluate (x+(i*10) for x in count()) until the end. But is this the right behaviour? How can I get the output I want: [0, 1, 2, 3, 4] [10, 11, 12, 13, 14] Thanks. Ken -- http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
Re: lazy evaluation is sometimes too lazy... help please.
itlist[i] = (x+(i*10) for i,s in (i,count()) for x in s) oops, that would be itlist[i] = (x+(i*10) for i,s in [(i,count())] for x in s) or equivalent, kind of ugly anyway. -- http://mail.python.org/mailman/listinfo/python-list
Re: lazy evaluation is sometimes too lazy... help please.
James Stroud jstr...@mbi.ucla.edu wrote: I'm going to get flamed pretty hard for this, but it doesn't seem to be the intuitive behavior to me either. Given this is the second time this issue has come up today, I'd have to agree with you. -- http://mail.python.org/mailman/listinfo/python-list
Re: Ordering of urlencoded tuples incorrect
On Jan 16, 1:44 am, John Machin sjmac...@lexicon.net wrote:
On Jan 16, 11:59 am, benluca...@googlemail.com wrote:
I'm having problems with the ordering of the tuples produced by
urllib.urlencode. Taking an example straight from the docs and so
doing the following:
What are the docs you are reading that include such an example? The
docs distributed with Python 2.5.1 fromwww.python.orghave only this:
urlencode( query[, doseq])
Convert a mapping object or a sequence of two-element tuples to a
``url-encoded'' string, suitable to pass to urlopen() above as the
optional data argument. This is useful to pass a dictionary of form
fields to a POST request. The resulting string is a series of
key=value pairs separated by characters, where both key and value
are quoted using quote_plus() above. If the optional parameter doseq
is present and evaluates to true, individual key=value pairs are
generated for each element of the sequence. When a sequence of two-
element tuples is used as the query argument, the first element of
each tuple is a key and the second is a value. The order of parameters
in the encoded string will match the order of parameter tuples in the
sequence. The cgi module provides the functions parse_qs() and
parse_qsl() which are used to parse query strings into Python data
structures.
import urllib
...
params = urllib.urlencode({'spam': 1, 'eggs': 2, 'bacon': 0})
print params
The documentation for urlencode( query[, doseq]) says: The order of
parameters in the encoded string will match the order of parameter
tuples in the sequence but I'm getting:
query can be either a mapping object (e.g. a dictionary, as you have
used) or a sequence of 2-tuples. No such guarantee as you quote above
can be made for a mapping; mappings are just not orderable.
If you want order, give it a sequence, like this:
| import urllib
| urllib.urlencode((('spam', 1), ('eggs', 2), ('bacon', 0)))
| 'spam=1eggs=2bacon=0'
HTH,
John
Thanks guys, the explanations really helped. I knew I was missing
something fundamental.
The docs I'm referring is section 18.7.3 Examples in the Python
Library Reference, 18th April, 2007, Release 2.5.1 But looking at it
now I guess the server side procsssing that post request may not care
about ordering (unlike the web API I'm trying to call).
cheers,
Ben
--
http://mail.python.org/mailman/listinfo/python-list
Re: reverse dict lookup Relation class
On Wed, 14 Jan 2009 16:30:36 -0800, Aaron Brady wrote:
Hi, this is a continuation of something that comes up now and again
about reverse lookups on dictionaries, as well as a follow-up to my
pursuit of a Relation class from earlier.
[...]
What's the best way to construct this class? Or, do you have an
argument that it could not be simpler than using a relational db?
Brainstorming, not flamestorming.
Here's a lightweight solution that uses lazy calculation of the reverse
dict. It makes a number of assumptions:
- both keys and values will be hashable and unique;
- the dict won't be so large that calculating the reverse dictionary will
be time consuming;
- modifications to instance.reverse are undefined.
Usage:
d = ReverseDict(x=2, y=3, z=4)
d['x']
2
d.reverse[2]
'x'
d['a'] = 0
d.reverse[0]
'a'
def make_dirty(func):
from functools import wraps
@wraps(func)
def f(self, *args, **kwargs):
self._dirty = True
return func(self, *args, **kwargs)
return f
# only tested a little bit
class ReverseDict(dict):
def __init__(self, *args, **kwargs):
super(ReverseDict, self).__init__(*args, **kwargs)
self._dirty = True
@make_dirty
def clear():
super(ReverseDict, self).clear()
@make_dirty
def __setitem__(self, key, value):
super(ReverseDict, self).__setitem__(key, value)
@make_dirty
def __delitem__(self, key):
super(ReverseDict, self).__delitem__()
@make_dirty
def pop(self, key, *arg):
return super(ReverseDict, self).pop(key, *arg)
@make_dirty
def popitem(self):
return super(ReverseDict, self).popitem()
@make_dirty
def setdefault(self, key, value=None):
return super(ReverseDict, self).setdefault(key, value)
@make_dirty
def update(self, other):
return super(ReverseDict, self).update(other)
@property
def reverse(self):
if self._dirty:
# Modify this to support repeated and non-hashable values.
self._reverse = dict((value, key) for
(key, value) in self.iteritems())
self._dirty = False
return self._reverse
An even more lightweight solution is to give up O(1) for the reverse
lookup:
# untested
class ReversableDict(dict):
def lookupvalue(self, value):
for k,v in self.iteritems():
if v == value: return k
raise ValueError('value not found')
def lookupallvalues(self, value):
results = []
for k,v in self.iteritems():
if v == value: results.append(k)
return results
--
Steven
--
http://mail.python.org/mailman/listinfo/python-list
Re: Python 3 isinstance
On Fri, 16 Jan 2009 09:58:53 +, Duncan Booth wrote: That still leaves the question whether anyone has ever actually taken advantage of this feature. You can do isinstance(x, (IntType, LongType, StringTypes)) but I didn't even know that StringTypes existed until a couple of moments ago, and I intend to forget about it again immediately. Grepping through the Python libraries on my system it looks like a lot of programmers don't even realise you can combine types into a tuple. I do it a lot, except I don't bother with IntType, LongType etc (I assume you imported them from the types module). I just do: isinstance(x, (int, float)) # or whatever -- Steven -- http://mail.python.org/mailman/listinfo/python-list
multiprocessing question/error
Hi, I was using the former processing package with python 2.5 with no problems. After switching to python 2.6.1 I am having some problems with the same code. The problem seems to be related to the fact that I am using Pool.map with a bounded method, since it is inside a class. To clarify a little bit, let me show some parts of the code class Pygen3(self) def calcula(self,indiv): def evaluate(self): indiv = range(mult*self.popsize,(mult+1)*self.popsize) pool = Pool(processes=nproc) results = pool.map(self.calcula,indiv) ... ... the error is the following Exception in thread Thread-1: Traceback (most recent call last): File /usr/lib/python2.6/threading.py, line 522, in __bootstrap_inner self.run() File /usr/lib/python2.6/threading.py, line 477, in run self.__target(*self.__args, **self.__kwargs) File /usr/lib/python2.6/multiprocessing/pool.py, line 225, in _handle_tasks put(task) PicklingError: Can't pickle type 'instancemethod': attribute lookup __builtin__.instancemethod failed Thanks for your help. -- Eduardo Lenz Cardoso Dr. Eng. Associate Professor State University of Santa Catarina Department of Mechanical Engineering 89223-100 - Joinville-SC - Brasil Tel: +55 47 4009-7971 - Fax: +55 47 4009-7940 E-mail: l...@joinville.udesc.br - -- Esta mensagem foi verificada pelo sistema de antiv�rus e acredita-se estar livre de perigo. -- http://mail.python.org/mailman/listinfo/python-list
Re: lazy evaluation is sometimes too lazy... help please.
On Fri, 16 Jan 2009 02:51:43 -0500, Ken Pu wrote: Hi, below is the code I thought should create two generates, it[0] = 0,1,2,3,4,5, and it[1] = 0,10,20,30,..., but they turn out to be the same!!! [...] I see what Python is doing -- lazy evaluation doesn't evaluate (x+(i*10) for x in count()) until the end. But is this the right behaviour? How can I get the output I want: [0, 1, 2, 3, 4] [10, 11, 12, 13, 14] The solution I would use is: itlist = [0,0] for i in range(2): itlist[i] = ( lambda i: (x+(i*10) for x in count()) )(i) Or pull the lambda out of the loop: itlist = [0,0] def gen(i): return (x+(i*10) for x in count()) for i in range(2): itlist[i] = gen(i) -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: mimetypes oddity
In article mailman.7301.1232043685.3487.python-l...@python.org, s...@pobox.com wrote: [mimetype weirdness reported] Sion Is this a bug? Might be. Can you file a bug report in the Python issue tracker with a small script that demonstrates the behavior? http://bugs.python.org/issue4963 (It's tagged as being 2.4 and 2.5 because those are the versions I have to hand to confirm it on, but I'd be rather surprised if it's not still like this in 2.6.) -- \S -- si...@chiark.greenend.org.uk -- http://www.chaos.org.uk/~sion/ Frankly I have no feelings towards penguins one way or the other -- Arthur C. Clarke her nu becomeþ se bera eadward ofdun hlæddre heafdes bæce bump bump bump -- http://mail.python.org/mailman/listinfo/python-list
Re: multiprocessing vs. distributed processing
On Fri, Jan 16, 2009 at 12:52 AM, James Mills prolo...@shortcircuit.net.au wrote: I've noticed over the past few weeks lots of questions asked about multi-processing (including myself). For those of you new to multi-processing, perhaps this thread may help you. Some things I want to start off with to point out are: multiprocessing will not always help you get things done faster. be aware of I/O bound applications vs. CPU bound multiple CPUs (cores) can compute multiple concurrent expressions - not read 2 files concurrently in some cases, you may be after distributed processing rather than multi or parallel processing cheers James James is quite correct, and maybe I need to amend the multiprocessing documentation to reflect this fact. While distributed programming and parallel programming may cross paths in a lot of problems/applications, you have to know when to use one versus the other. Multiprocessing only provides some basic primitives to help you get started with distributed programming, it is not it's primary focus, nor is it a complete solution for distributed applications. That being said, there is no reason why you could not use it in conjunction with something like Kamaelia, pyro, $ipc mechanism/etc. Ultimately, it's a tool in your toolbox, and you have to judge and experiment to see which tool is best applied to your problem. In my own work/code, I use both processes *and* threads - one works better than the other depending on the problem. For example, a web testing tool. This is something that needs to generate hundreds of thousands of HTTP requests - not a problem you want to use multiprocessing for given that A It's primarily I/O bound and B You can generate that many threads on a single machine. However, if I wanted to say, generate hundreds of threads across multiple machines, I would (and do) use multiprocessing + paramiko to construct a grid of machines and coordinate work. That all being said: multiprocessing isn't set in stone - there's room for improvement in the docs, tests and code, and all patches are welcome. -jesse -- http://mail.python.org/mailman/listinfo/python-list
Integrating awk in Python
Hello, I'm developing a software package using python. I've programmed all necessary tools but I have to use other stuff from other people. Most of these external scripts are developed using awk. At the beggining I thought to translate them and program them in python but I prefer to avoid it because it means a lot of work and I should do it after each new version of this external stuff. I would like to integrate them into my python code. I know I can call them using the system environment but it is slower than if I call them inside the package. I know it is possible with C, do you have experience on integrate awk into python calling these awk scripts from python? Thanks in advance! Regards, Alfons. -- Alfons Nonell-Canals, PhD Chemogenomics Lab Research Group on Biomedical Informatics (GRIB) - IMIM/UPF Barcelona Biomedical Research Park (PRBB) C/ Doctor Aiguader, 88 - 08003 Barcelona alfons.non...@upf.edu - http://cgl.imim.es Tel. +34933160528 http://alfons.elmeuportal.cat http://www.selenocisteina.info -- http://mail.python.org/mailman/listinfo/python-list
Re: process/thread instances and attributes
On Thu, Jan 15, 2009 at 10:37 PM, James Mills prolo...@shortcircuit.net.au wrote: After some work ... I've taken Laszlo's suggestion of using Value (shared memory) objects to share state between the -pseudo- Process (manager) object and it's underlying multiprocessing.Process instance (and subsequent process): Here is the code: #!/usr/bin/env python import os from time import sleep from threading import activeCount as threads from threading import Thread as _Thread from multiprocessing import Value from multiprocessing import Process as _Process from multiprocessing import active_children as processes class Process(object): def __init__(self, *args, **kwargs): super(Process, self).__init__(*args, **kwargs) self.running = Value(b, False) self.thread = _Thread(target=self.run) self.process = _Process(target=self._run, args=(self.running,)) def _run(self, running): self.thread.start() try: while running.value: try: sleep(1) print ! except SystemExit: running.acquire() running.value = False running.release() break except KeyboardInterrupt: running.acquire() running.value = False running.release() break finally: running.acquire() running.value = False running.release() self.thread.join() def start(self): self.running.acquire() self.running.value = True self.running.release() self.process.start() def run(self): pass def stop(self): print %s: Stopping ... % self self.running.acquire() self.running.value = False self.running.release() def isAlive(self): return self.running.value class A(Process): def run(self): while self.isAlive(): sleep(5) self.stop() a = A() a.start() N = 0 while a.isAlive(): sleep(1) print . print threads: %d % threads() print processes: %d % len(processes()) print DONE Here is the result of running this: $ python test3.py ! . threads: 1 processes: 1 . threads: 1 processes: 1 ! ! . threads: 1 processes: 1 . threads: 1 processes: 1 ! . threads: 1 processes: 1 ! __main__.A object at 0x80de42c: Stopping ... ! . threads: 1 processes: 0 DONE This appears to work as I intended. Thoughts / Comments ? cheers James Personally, rather then using a value to indicate whether to run or not, I would tend to use an event to coordinate start/stop state. -jesse -- http://mail.python.org/mailman/listinfo/python-list
Re: Integrating awk in Python
Hi, take a look at the 5th link at http://tinyurl.com/7s8kfq It's called pyawk. Regards, wr Am Freitag, 16. Januar 2009 13:02:59 schrieb Alfons Nonell-Canals: Hello, I'm developing a software package using python. I've programmed all necessary tools but I have to use other stuff from other people. Most of these external scripts are developed using awk. At the beggining I thought to translate them and program them in python but I prefer to avoid it because it means a lot of work and I should do it after each new version of this external stuff. I would like to integrate them into my python code. I know I can call them using the system environment but it is slower than if I call them inside the package. I know it is possible with C, do you have experience on integrate awk into python calling these awk scripts from python? Thanks in advance! Regards, Alfons. -- http://mail.python.org/mailman/listinfo/python-list
Re: List comprehension - NameError: name '_[1]' is not defined ?
On Jan 16, 5:09 am, mario ruggier mario.rugg...@gmail.com wrote: Laboriously doing all these checks on each expr eval will be very performance heavy, so I hope to be able to limit access to all these more efficiently. Suggestions? None regarding the general issue, a try:except to handle this one: '(x for x in ()).throw(bork)' -- http://mail.python.org/mailman/listinfo/python-list
Re: Does Python really follow its philosophy of Readability counts?
Russ P. wrote: [...] I spent *way* too much time on that post. I really need to quit spending my time refuting the baloney that passes for wisdom here. He who cannot ignore baloney is doomed to refute it. regards Steve -- Steve Holden+1 571 484 6266 +1 800 494 3119 Holden Web LLC http://www.holdenweb.com/ -- http://mail.python.org/mailman/listinfo/python-list
vb2py status?
G'day everyone So is vb2py dead? If not, any idea when it'll support python 3? Kind regards, Bruce. -- http://mail.python.org/mailman/listinfo/python-list
Experiment: Church lists in Python
Hello there Pythoners, It was almost a week ago, when I got bored and thought, Python is quite a boring language, so I'd need to do some evil functional programming again. I thought, I'd share the result. ;) This time, I added a Church style representation for lists [1] to Python. The problem they solve: What do you do, if you've got only scalar values, functions and function application, but you need lists? Here is the solution: Represent lists as higher order functions: def empty(): return lambda f, z: z def cons(x, xs): return lambda f, z: f(x, xs(f, z)) def fold(f, z, xs): return xs(f, z) The empty() function returns an empty list and the cons() function returns the list in its second argument with the element in its first argument prepended, so cons(x, xs) is equivalent to the list [x] + xs. The 'fold' function is actually superfluous, but it makes much clearer what you're doing, when using this type of lists. It's the right-associative version of the 'reduce' function. All other list operations can be defined in terms of these three functions. I've done that for you [2] (mostly). If Python implements closures efficiently, this list representation is actually very fast for list folding, i.e. consuming an entire list to construct a value (which may be anything, including lists or functions). However, it's slow for extracting individual elements, because this operation must be a fold, too, as folding is the only way to access the elements of a list. An interesting property of this representation is that it gets along without any impure functions, i.e. all functions are completely free of side effects. Unless you use an impure fold function, everything is perfectly purely functional. Have fun. =) Greets, Ertugrul. [1] http://en.wikipedia.org/wiki/Church_encoding#Higher-order-function, a representation of a list as a higher order function. [2] http://ertes.de/python/fun/chlists.py, a little library of Python functions implementing Church style lists using higher order functions. The way the 'range' function is defined, was an experiment: how to emulate partial application in Python. Greets, Ertugrul. -- nightmare = unsafePerformIO (getWrongWife = sex) http://blog.ertes.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Soap Client
I believe that I have answered my own question. If anyone else is interested in what I did ... using iPython's code completion (. then hit tab tab) I noticed that msg had a _request attribute. I set that attribute to GetEventListMonth1/Month/GetEventList and that sent the message that I needed! Hope everyone has a great day! Doug -- http://mail.python.org/mailman/listinfo/python-list
Re: English-like Python
On Jan 16, 3:15 am, alex23 wuwe...@gmail.com wrote: On Jan 16, 5:39 pm, Erik Max Francis m...@alcyone.com wrote: Inform 7 has some interesting ideas, but I think the general problem with English-like programming language systems is that once you get into the nitty gritty details, you end up having to know exactly the right things to type, This has always been my impression of Inform 7. I have a lot of respect for what they've set out to achieve but English isn't exactly known for its lack of ambiguity. This is great for literature but not so helpful for programming. which ultimately get just as complicated as a more traditional programming language syntax. And much more verbose, as well. Since I've used Inform 7 I can say that the syntactic problem isn't that great: once you get far enough into a project to matter the specialized constraints just sink in. It's more work to learn, but no stranger than Python's indentation scheme. The bigger problem for the comparison is that Inform 7 is a Domain Specific Language (DSL), not a general purpose language. Not only that, but the domain is pretty much everyday experience (with a large dollop of fantasy, of course). All the feedback is that the results are quite readable to non-programmers. This is why well over half of the mailing list posts on the authoring mailing list are about Inform 7. I really don't think that using natural language for a general purpose programming language is a good idea, for reasons that several other people have already said. I think it's a great idea for DSLs, at least in some cases. The other really major problem is that I don't think anyone really knows how to process natural language. The direction that natural language processing has taken in the last 50 years has come up lacking big-time. It does a good job in a single domain, but try to build something that crosses domains and nothing works. There isn't a good alternative in sight John Roth -- http://mail.python.org/mailman/listinfo/python-list
Re: Readline and Python 2.6.1 on a Mac
s/bind ^I rl_complete/tab: complete/ http://tiswww.case.edu/php/chet/readline/readline.html -- Ned Deily, n...@acm.org Perfect, thanks Ned! -- http://mail.python.org/mailman/listinfo/python-list
Re: Python 3 isinstance
Steven D'Aprano st...@remove-this-cybersource.com.au wrote: On Fri, 16 Jan 2009 09:58:53 +, Duncan Booth wrote: That still leaves the question whether anyone has ever actually taken advantage of this feature. You can do isinstance(x, (IntType, LongType, StringTypes)) but I didn't even know that StringTypes existed until a couple of moments ago, and I intend to forget about it again immediately. Grepping through the Python libraries on my system it looks like a lot of programmers don't even realise you can combine types into a tuple. I do it a lot, except I don't bother with IntType, LongType etc (I assume you imported them from the types module). I just do: isinstance(x, (int, float)) # or whatever Yes, I do that too, and naturally I don't use the types module. The question though was whether anyone, anywhere, has ever taken advantage of the fact that isinstance accepts *nested* tuples. My point was intended to be that perhaps if someone imported from the types module they might just use StringTypes in a tuple along with the single type names, but it seems pretty unlikely to be common usage. -- Duncan Booth http://kupuguy.blogspot.com -- http://mail.python.org/mailman/listinfo/python-list
Re: Does Python really follow its philosophy of Readability counts?
Quoting Russ P. russ.paie...@gmail.com: On Jan 15, 12:21 pm, Bruno Desthuilliers bdesth.quelquech...@free.quelquepart.fr wrote: Once again, the important point is that there's a *clear* distinction between interface and implementation, and that you *shouldn't* mess with implementation. If you *shouldn't* mess with the implementation, then what is wrong with enforcing that shouldn't in the language itself? Because, as a library user, it should be my power to chose when and how I _should_ mess with the implementation, not the compiler, and definitely not you. So let's take the airplane example. Boeing and its contractors probably has hundreds of programmers working on millions of lines of code. If they believed you, they would abandon enforced data hiding, and programmers would have much more discretion to screw around with code that they don't work on directly. An FMS programmer could perhaps decide to change the parameters of the engine controls, for example. I really hope that, at Boeing, they do a lot of unit tests and code reviews before the code is commited. Messing with the internals wouldn't be the only bad thing that could happen, you know... And I'd say that x._private where x is not 'self', would be very easy to catch on those code reviews. And, as someone else pointed out, even with 'strong' enforcement of data-hiding, you can usually access the privates anyway - it's just a bit harder to do, and a lot harder to discover. You pointed out previously that Python wasn't up to the task of running untrusted code on my own application, and I agreed. _That_ is what you seem need, and enforced data hiding does very little towards it. -- Luis Zarrabeitia Facultad de Matemática y Computación, UH http://profesores.matcom.uh.cu/~kyrie -- http://mail.python.org/mailman/listinfo/python-list
Re: Does Python really follow its philosophy of Readability counts?
Paul Rubin wrote: 1) Parallelism. Commodity desktop computers now have 8 effective cpu cores or maybe even 16 soon (Mac Pro, Intel Core i7) but Python still has the evil GIL that forces all threads to run on one core. Java, Erlang, and Haskell (GHC) all beat Python in this area. By the time Python 4 comes out, we will probably all be using PC's with 32 or more cores, so the current limitations will be intolerable. Even today, since no one doing anything serious uses single core machines any more, the GIL is a huge pain in the neck which the multiprocessing module helps only slightly. (While we are at it, lightweight threads like Erlang's or GHC's would be very useful.) +100 for this one 2) Native-code compilation. Per the Alioth shootouts, Python is much slower (even on single cores) than Java, Haskell, ML, or even Scheme. PyPy is addressing this but it will be a while before it replaces CPython. The lack of this already causes some pains at my company. I was flabbergasted to read that optional static typing was dropped by Guido due to lack of interest in community IIRC. Why!! Among other reasons, this could have provided for very easy performance optimizations of the small portions of the code! This could have been a huge gain acquired for little effort! Regards, mk -- http://mail.python.org/mailman/listinfo/python-list
Re: English-like Python
[Hit Reply instead of Reply All. Sorry alex23.] alex23 wrote: On Jan 16, 5:39 pm, Erik Max Francis m...@alcyone.com wrote: Inform 7 has some interesting ideas, but I think the general problem with English-like programming language systems is that once you get into the nitty gritty details, you end up having to know exactly the right things to type, This has always been my impression of Inform 7. I have a lot of respect for what they've set out to achieve but English isn't exactly known for its lack of ambiguity. This is great for literature but not so helpful for programming. which ultimately get just as complicated as a more traditional programming language syntax. And much more verbose, as well. I once had to do something in AppleScript. The problem I found was that it tried so much to resemble English that it wasn't always clear what was valid! Programming languages need to look artificial to remind you that the computers aren't intelligent. Python, for example, is clearly artificial but with a clear syntax and short (but not too short) reserved words. -- http://mail.python.org/mailman/listinfo/python-list
Re: Client Socket Connection to Java server
TechieInsights wrote: I am having problems with a socket connection to a Java server. In java I just open the socket, pass the length and then pass the bits across the socket. I created a socket object: import socket class MySocket: def __init__(self, host='localhost', port = 28192, buffsize = 1024): socket.setdefaulttimeout(10) self.host = host self.port = port self.buffsize = buffsize self.socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM) self.socket.connect((host, port)) def send(self, data): self.socket.send(data) I recommend sendall() instead of send(): self.socket.sendall(data) send() doesn't guarantee to send all the data, so multiple sends might be needed to send it all. sendall() does that for you. def receive(self): return self.socket.recv(self.buffsize) def sendAndReceive(self, data): self.send(data) return self.receive() def close(self): self.socket.close() But the java server gives the error: WARNING: Incoming Message length invalid. Discarding The data is of type string (xml). Am I doing something wrong? I know you have to reverse the bits when communicating from C++ to Java. Could this be the problem? I figured it would not because it said the length was invalid. I just started looking at python sockets tonight... and I don't have a real deep base with socket connections as it is... any help would be greatly appreciated. Greg -- http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
Re: Start two threads in same time
On Jan 16, 7:36 pm, vedrandeko...@gmail.com wrote: Hello, Does anybody know how can I start two threads in same time? Regards, John Use threading module. Creating a new thread is as easy as -- --- import threading class ThreadedClass(threading.Thread): def __init__(self): threading.Thread.__init__(self) def run(self): **Do whatever you want do in the new thread here** threaded_obj = ThreadedClass() threaded_obj.setDaemon(True) # If you want a daemon thread threaded_obj.start() # Start the new thread Do whatever you want to do in main thread here%%% threaded_obj.join() #Close the new thread by joining it with the main thread The following document might be of help: http://heather.cs.ucdavis.edu/~matloff/Python/PyThreads.pdf -- http://mail.python.org/mailman/listinfo/python-list
Re: Convention vs. fascism [OT]
Steven D'Aprano st...@remove-thisurce.com.au wrote: And... skull socks? Cool. Where can I get some? Don't you remember? - Google the group - there was some dust raised about them some time ago. I think he got them from KDW - Kaufhaus Der Welt aka Klau Dir Was :-) - Hendrik -- http://mail.python.org/mailman/listinfo/python-list
Re: Start two threads in same time
On Jan 16, 7:46 pm, koranthala koranth...@gmail.com wrote: On Jan 16, 7:36 pm, vedrandeko...@gmail.com wrote: Hello, Does anybody know how can I start two threads in same time? Regards, John Use threading module. Creating a new thread is as easy as -- --- import threading class ThreadedClass(threading.Thread): def __init__(self): threading.Thread.__init__(self) def run(self): **Do whatever you want do in the new thread here** threaded_obj = ThreadedClass() threaded_obj.setDaemon(True) # If you want a daemon thread threaded_obj.start() # Start the new thread Do whatever you want to do in main thread here%%% threaded_obj.join() #Close the new thread by joining it with the main thread The following document might be of help:http://heather.cs.ucdavis.edu/~matloff/Python/PyThreads.pdf If you want to create n threads, just create and call the threaded_obj n times. So, the code will look like: threaded_obj = [] for i in range(n): threaded_obj[i] = ThreadedClass() threaded_obj[i].setDaemon(True) # If you want a daemon thread threaded_obj[i].start() # Start the new thread Do whatever you want to do in main thread here%%% #To close the threads for o in threaded_obj: o.join() --HTH-- -- http://mail.python.org/mailman/listinfo/python-list
Re: Problem using python C API
On Jan 16, 2009, at 5:31 AM, shi dingan wrote:
void initexample() {
PyObject *m;
m = Py_InitModule(example, exampleMethods);
}
When I try to import examplemodule, I obtain the following message:
import examplemodule
Traceback (most recent call last):
File stdin, line 1, in ?
ImportError: dynamic module does not define init function
(initexamplemodule)
Hi Marc,
The tutorial says, The initialization function must be named
initname(), where name is the name of the module. The error message
you got is very accurate: module does not define init function
(initexamplemodule). Since your module is called examplemodule,
Python is looking for a function called initexamplemodule.
Change your build step to build a module called example and not
examplemodule and I think you'll be OK.
bye
Philip
--
http://mail.python.org/mailman/listinfo/python-list
Re: English-like Python
On Jan 16, 8:39 am, Erik Max Francis m...@alcyone.com wrote: I was thinking of this as well when I saw his post. Inform 7 has some interesting ideas, but I think the general problem with English-like programming language systems is that once you get into the nitty gritty details, you end up having to know exactly the right things to type, which ultimately get just as complicated as a more traditional programming language syntax. In the big picture I don't think it helps much. After all, there's a reason that most modern programming languages don't look like COBOL or AppleScript. COBOL looks like English to facilitate reading programs, not writing them. COBOL is for use in places where programs must be read and verified by possibly computer-illiterate personnel. E.g. in bank and finance where (at least in some countries) everything must be supervised and approved by professional accountants. COBOL is still the dominating language in that domain. -- http://mail.python.org/mailman/listinfo/python-list
bubblefishymon
Hi Guys I am trying to get bubblefishymon to work as a gdesklet. (app is written in python) The app seems to work, but it does display any water. I'm assuming its because it cant poll the network card etc. If I try run it on the command line it shows this error : $ python __init__.py Traceback (most recent call last): File __init__.py, line 3, in module from sensor.Sensor import Sensor ImportError: No module named sensor.Sensor In the dekslets log it also shows this : Deprecation: Sensors are deprecated since v0.30. Please consider using controls and inline scripts. Does that mean Sensors is no longer used / supported ? If so , what do I use in place of it ? Please note, I don't know how to code in Python (yet!) so any help would be much appreciated. Regards Andy -- http://mail.python.org/mailman/listinfo/python-list
Re: Problem using python C API
Right, thx for your reply, I completely overlooked examplemodule.so
in the building step. Maybe I should sleep more these days :)
Btw, I've now an other problem with PyArg_ParseTuple but I guess
it is better to post in the capi-sig mailing list.
Thx again,
Marc.
On Jan 16, 2009, at 5:31 AM, shi dingan wrote:
void initexample() {
PyObject *m;
m = Py_InitModule(example, exampleMethods);
}
When I try to import examplemodule, I obtain the following message:
import examplemodule
Traceback (most recent call last):
File stdin, line 1, in ?
ImportError: dynamic module does not define init function
(initexamplemodule)
Hi Marc,
The tutorial says, The initialization function must be named
initname(), where name is the name of the module. The error message
you got is very accurate: module does not define init function
(initexamplemodule). Since your module is called examplemodule,
Python is looking for a function called initexamplemodule.
Change your build step to build a module called example and not
examplemodule and I think you'll be OK.
bye
Philip
--
http://mail.python.org/mailman/listinfo/python-list
--
http://mail.python.org/mailman/listinfo/python-list
Re: Does Python really follow its philosophy of Readability counts?
Paul Rubin wrote: But, if something is done by convention, then departing from the convention is by definition unconventional. If you do something unconventional in a program, it could be on purpose for a reason, or it could be by accident indicating a bug. I for one would love to see at least compiler warning (optionally, error) for situation where attributes are added to self outside of __init__. I consider it generally evil and hate to see code like that. Regards, mk -- http://mail.python.org/mailman/listinfo/python-list
confused about publishing more than one class in twisted server.
hello, I am writing a twisted based rpc service where I am implementing a complete application as a service. I have many modules which make a package. Now when we publish a service in twisted, we have to create one instance of a certain class and then publish it with the help of reactor. but in my application, there are more than one class in different .py files. Now I want to know how do i create a package where all the classes in different modules get published so that the entire package can be used as the rpc server application and the client can be used to query any module. for example I have classes to get and set vendor, product, bills etc. now all this has to be accessed through the xml rpc service. Can some one tell me how to manage the entire twisted package as a service. happy hacking. Krishnakant. -- http://mail.python.org/mailman/listinfo/python-list
Start multiple listening servers in one file
I`m working on a django-project where I`m using the awsome pyftpdlib for ftpserver-functionality. I also have a simple worker deamon running in the background, but not listening to any port. How can I start all of these processes on one file? Tried using subprocess and popen but that resulted in an eternal loop starting the servers over and over until all resources were used, then crash. Any hint on how to do this would be highly appreciated. -- http://mail.python.org/mailman/listinfo/python-list
Start two threads in same time
Hello, Does anybody know how can I start two threads in same time? Regards, John -- http://mail.python.org/mailman/listinfo/python-list
Skull Socks (was Re: Convention vs. fascism)
On Fri, 2009-01-16 at 08:57 +, Steven D'Aprano wrote: On Fri, 16 Jan 2009 10:03:28 +0200, Hendrik van Rooyen wrote: Oh come on you lot - you are carrying on as if Diez were wearing his skull socks again - do me a favour and give him a break! And... skull socks? Cool. Where can I get some? http://www.letmegooglethatforyou.com/search?q=skull+socks -- http://mail.python.org/mailman/listinfo/python-list
Re: Skull Socks (was Re: Convention vs. fascism)
On Fri, 16 Jan 2009 11:01:18 -0500, J. Cliff Dyer wrote: On Fri, 2009-01-16 at 08:57 +, Steven D'Aprano wrote: On Fri, 16 Jan 2009 10:03:28 +0200, Hendrik van Rooyen wrote: Oh come on you lot - you are carrying on as if Diez were wearing his skull socks again - do me a favour and give him a break! And... skull socks? Cool. Where can I get some? http://www.letmegooglethatforyou.com/search?q=skull+socks Not Found The requested URL /search was not found on this server. Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request. You know, it was just a throw-away comment to lighten the mood. I don't really need to see 18,000+ links to places that sell socks with skulls printed on them. On the other hand, if they were socks made from actual skulls, that would be something... -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: Client Socket Connection to Java server
Hint: Java sends a '\n' character at the end. -- http://mail.python.org/mailman/listinfo/python-list
Re: Does Python really follow its philosophy of Readability counts?
mk mrk...@gmail.com writes: I was flabbergasted to read that optional static typing was dropped by Guido due to lack of interest in community IIRC. I don't remember that happening. PEP 3107 still lists type checking as a use case for Python 3.0 function annotations. -- http://mail.python.org/mailman/listinfo/python-list
Re: Integrating awk in Python
Willi Richert wrote: Hi, take a look at the 5th link at http://tinyurl.com/7s8kfq It's called pyawk. Stupid link wanting to set yet another useless cookie. Answer will not always be 5th. Just say 'Google pyawk' or better give link http://pyawk.sourceforge.net/ Am Freitag, 16. Januar 2009 13:02:59 schrieb Alfons Nonell-Canals: Hello, I'm developing a software package using python. I've programmed all necessary tools but I have to use other stuff from other people. Most of these external scripts are developed using awk. At the beggining I thought to translate them and program them in python but I prefer to avoid it because it means a lot of work and I should do it after each new version of this external stuff. I would like to integrate them into my python code. I know I can call them using the system environment but it is slower than if I call them inside the package. I know it is possible with C, do you have experience on integrate awk into python calling these awk scripts from python? -- http://mail.python.org/mailman/listinfo/python-list
Re: English-like Python
2009/1/16 The Music Guy music...@alphaios.net: Just out of curiousity, have there been any attempts to make a version of Python that looks like actual English text? I mean, so much of Python is already based on the English language that it seems like the next natural step would be to make a programming language which is actually a spoken one. This one is close: http://en.wikipedia.org/wiki/Brainfuck -- Dotan Cohen http://what-is-what.com http://gibberish.co.il א-ב-ג-ד-ה-ו-ז-ח-ט-י-ך-כ-ל-ם-מ-ן-נ-ס-ע-ף-פ-ץ-צ-ק-ר-ש-ת ا-ب-ت-ث-ج-ح-خ-د-ذ-ر-ز-س-ش-ص-ض-ط-ظ-ع-غ-ف-ق-ك-ل-م-ن-ه-و-ي А-Б-В-Г-Д-Е-Ё-Ж-З-И-Й-К-Л-М-Н-О-П-Р-С-Т-У-Ф-Х-Ц-Ч-Ш-Щ-Ъ-Ы-Ь-Э-Ю-Я а-б-в-г-д-е-ё-ж-з-и-й-к-л-м-н-о-п-р-с-т-у-ф-х-ц-ч-ш-щ-ъ-ы-ь-э-ю-я ä-ö-ü-ß-Ä-Ö-Ü -- http://mail.python.org/mailman/listinfo/python-list
Re: mimetypes oddity
Sion Arrowsmith wrote:
In article mailman.7301.1232043685.3487.python-l...@python.org,
s...@pobox.com wrote:
[mimetype weirdness reported]
Sion Is this a bug?
Might be. Can you file a bug report in the Python issue tracker with a
small script that demonstrates the behavior?
http://bugs.python.org/issue4963
(It's tagged as being 2.4 and 2.5 because those are the versions I
have to hand to confirm it on, but I'd be rather surprised if it's
not still like this in 2.6.)
Trying to reproduce a bug, as this report requires, is easier if you
give code that can be copy and pasted into the interpreter or even into
an edit window (as with IDLE) to be run from there. (3.0 version)
import mimetypes
print(mimetypes.guess_extension('image/jpeg'))
mimetypes.init()
print(mimetypes.guess_extension('image/jpeg'))
--
http://mail.python.org/mailman/listinfo/python-list
Python 2.6's multiprocessing lock not working on second use?
Hi,
I ran a few tests on the new Python 2.6 multiprocessing module before
migrating a threading code, and found out the locking code is not
working well. In this case, a pool of 5 processes is running, each
trying to get the lock and releasing it after waiting 0.2 seconds
(action is repeated twice). It looks like the multiprocessing lock
allows multiple locking after the second pass. Running the exact same
code with threads works correctly.
Further down is the test code, output is great when running with
threads (the sequence of lock/unlock looks good), but the output gets
mixed up (mutliple locks in a row) when running with processes.
My setup is : Mac OS X 10.5 running Python 2.6.1 from MacPython
Did I do something wrong, or is there a limitation for multiprocessing
locks that I am not aware of?
Thank you for your help!
-- Fred
---
#!/usr/bin/python
# -*- coding: utf-8 -*-
from multiprocessing import Process, Queue, Lock
from Queue import Empty
from threading import Thread
import time
class test_lock_process(object):
def __init__(self, lock, id, queue):
self.lock = lock
self.id = id
self.queue = queue
self.read_lock()
def read_lock(self):
for i in xrange(2):
self.lock.acquire()
self.queue.put('[proc%d] Got lock' % self.id)
time.sleep(.2)
self.queue.put('[proc%d] Released lock' % self.id)
self.lock.release()
def test_lock(processes=10, lock=Lock(), process=True, queue=None):
print_result = False
if queue == None:
print_result = True
queue = Queue()
threads = []
for i in xrange(processes):
if process: threads.append(Process(target=test_lock_process,
args=(lock,i,queue,)))
else: threads.append(Thread(target=test_lock_process, args=
(lock,i,queue,)))
for t in threads:
t.start()
for t in threads:
t.join()
if print_result:
try:
while True: print queue.get(block=False)
except Empty:
pass
if __name__ == __main__:
#test_lock(processes=5, process=True)
test_lock(processes=5)
--
http://mail.python.org/mailman/listinfo/python-list
Re: Possible bug in Tkinter - Python 2.6
Eric Brunel wrote: On Thu, 15 Jan 2009 23:49:22 +0100, Terry Reedy tjre...@udel.edu wrote: Eric Brunel wrote: [snip] And BTW, if this is actually a bug, where can I report it? bugs.python.org Thanks. I reported the problem. When you report that you reported to problem to the tracker (a good idea), please include link so anyone reading this thread can jump there to continue with followup there. -- http://mail.python.org/mailman/listinfo/python-list
Re: optimizing large dictionaries
On Jan 15, 4:39 pm, Per Freem perfr...@yahoo.com wrote: hello i have an optimization questions about python. i am iterating through a file and counting the number of repeated elements. the file has on the order of tens of millions elements... i create a dictionary that maps elements of the file that i want to count to their number of occurs. so i iterate through the file and for each line extract the elements (simple text operation) and see if it has an entry in the dict: for line in file: try: elt = MyClass(line)# extract elt from line... my_dict[elt] += 1 except KeyError: my_dict[elt] = 1 i am using try/except since it is supposedly faster (though i am not sure about this? is this really true in Python 2.5?). the only 'twist' is that my elt is an instance of a class (MyClass) with 3 fields, all numeric. the class is hashable, and so my_dict[elt] works well. the __repr__ and __hash__ methods of my class simply return str() representation of self, while __str__ just makes everything numeric field into a concatenated string: class MyClass def __str__(self): return %s-%s-%s %(self.field1, self.field2, self.field3) def __repr__(self): return str(self) def __hash__(self): return hash(str(self)) is there anything that can be done to speed up this simply code? right now it is taking well over 15 minutes to process, on a 3 Ghz machine with lots of RAM (though this is all taking CPU power, not RAM at this point.) any general advice on how to optimize large dicts would be great too thanks for your help. I am willing to bet a beer that the slow performance has nothing to do with the dict but is either because of MyClass or the read from disk. -- http://mail.python.org/mailman/listinfo/python-list
Re: Beginner: Data type conversion question
On Jan 15, 11:35 pm, Terry Reedy tjre...@udel.edu wrote: flagg wrote: I am still fairly new to python and programming in general. My question is regardingdataconversion, I am working on a script that will edit dns zone files, one of the functions i wrote handles updating the serial number. Our zone files use the date as the first part of the serial and a two digit integer as the last two. i.e. 2009011501. The next update would be 2009011502, etc Here is the function I wrote, I am using dnspython for reading in zone files as Zone objects. Because dnspython's built-in serial updater will not work with how we format our serial's, I have to re-write it. def checkSerial(): Checks the current 'date' portion of the serial number and checks the current 'counter'(the two digit number at the end of the serial number), then returns a complete new serial currentDate = time.strftime(%Y%m%d, time.localtime()) for (name, ttl, rdata) in zone.iterate_rdatas(SOA): date = str(rdata.serial)[0:8] inc = str(rdata.serial)[8:10] If rdate.serial is already a string, as name would imply, the str() call is pointless. If not, can you get inc as int more directly? if date == currentDate: int(inc) + 1 print inc newInc = str(inc).zfill(2) serial = date + newInc print date is the same return serial elif date currentDate: newInc = 01.zfill(2) serial = currentDate + newInc print date is different return serial Through all of this I am doing a lot ofdatatypeconversion. string - integer, integer back to string, etc. Is this an efficient way of handling this? I have to perform basic addition on the inc variable, but also need to expose that value as a string. What I have above does work, but I can't help but think there is a more efficient way. I guess I am not used todatatypes being converted so easily. Other than that, you are perhaps worrying too much, even if code could be squeezed more. The idea that every object knows how to convert itself to a string representation is basic to Python. tjr Actually when i run a type(serial) on that variable it returns a long which i am not sure why dnspython uses a long variable to store the serial. But you could be right about me worrying to much. The other languages I have dabbled in (java, perl) I don't remember type conversion being as simple. But again I am still new, so don't quote me on that :) -- http://mail.python.org/mailman/listinfo/python-list
Re: lazy evaluation is sometimes too lazy... help please.
Ken Pu wrote: Hi, below is the code I thought should create two generates, it[0] = 0,1,2,3,4,5, and it[1] = 0,10,20,30,..., but they turn out to be the same!!! from itertools import * itlist = [0,0] for i in range(2): itlist[i] = (x+(i*10) for x in count()) ... print list(islice(itlist[0], 5)) print list(islice(itlist[1], 5)) ... -- lazy evaluation doesn't evaluate (x+(i*10) for x in count()) until the end. Nope, that generator expression is evaluated in your assignment. The expression x+(i*10) is evaluated at each step of the generator. But is this the right behaviour? It is the defined behavior. For what you want: import itertools as it def count_from(base): for n in it.count(): yield n + base itlist = [count_from(n) for n in range(2)] --Scott David Daniels scott.dani...@acm.org -- http://mail.python.org/mailman/listinfo/python-list
Re: Integrating awk in Python
Alfons Nonell-Canals wrote: At the beggining I thought to translate them and program them in python but I prefer to avoid it because it means a lot of work and I should do it after each new version of this external stuff. I would like to integrate them into my python code. That's kind of like retrofitting steam engine onto a Mach 2 jetfighter. Well there's always awk2c.. Regards, mk -- http://mail.python.org/mailman/listinfo/python-list
Re: Beginner: Data type conversion question
On Jan 15, 11:43 pm, Marc 'BlackJack' Rintsch bj_...@gmx.net wrote: On Thu, 15 Jan 2009 21:09:43 -0800, flagg wrote: def checkSerial(): Checks the current 'date' portion of the serial number and checks the current 'counter'(the two digit number at the end of the serial number), then returns a complete new serial currentDate = time.strftime(%Y%m%d, time.localtime()) The format string can be written as *one* string literal instead of three: %Y%m%d. for (name, ttl, rdata) in zone.iterate_rdatas(SOA): date = str(rdata.serial)[0:8] inc = str(rdata.serial)[8:10] Here you are converting `rdata.serial` twice. tmp = str(rdata.serial) date = tmp[0:8] inc = int(tmp[8:10]) As `inc` is conceptually a number, you should do theconversionhere and treat it as number from now on. if date == currentDate: int(inc) + 1 print inc newInc = str(inc).zfill(2) serial = date + newInc print date is the same return serial elif date currentDate: newInc = 01.zfill(2) serial = currentDate + newInc print date is different return serial Both branches do almost the same. You should try to avoid such code duplication. if date == currentDate: inc += 1 elif date currentDate: inc = 1 else: assert False # Should never happen. return %s%02d % (date, inc) That's it. Ciao, Marc 'BlackJack' Rintsch Ah return %s%02d % (date, inc) This piece is what I was missing in my original design. I couldn't figure out hot to take and integer and force it to my double digit. i.e. 01 instead of 1. Which is why I was using strings to make that happen. (obviously incorrectly). Thanks Could you explain what assert does in the if statement. I am assuming if the first two conditions are not met, it will hit assert false and exit the program? -- http://mail.python.org/mailman/listinfo/python-list
Python 3: range objects cannot be sliced
Is the behavior below expected? Documented? (The error msg is misleading.) Thanks, Alan Isaac x = range(20) s = slice(None,None,2) x[s] Traceback (most recent call last): File stdin, line 1, in module TypeError: sequence index must be integer, not 'slice' -- http://mail.python.org/mailman/listinfo/python-list
Re: List comprehension - NameError: name '_[1]' is not defined ?
On Jan 16, 1:35 pm, ajaksu aja...@gmail.com wrote: On Jan 16, 5:09 am, mario ruggier mario.rugg...@gmail.com wrote: Laboriously doing all these checks on each expr eval will be very performance heavy, so I hope to be able to limit access to all these more efficiently. Suggestions? None regarding the general issue, a try:except to handle this one: '(x for x in ()).throw(bork)' What is the potential security risk with this one? To handle this and situations like the ones pointed out above on this thread, I will probably affect the following change to the evoque.evaluator.RestrictedEvaluator class, and that is to replace the 'if name.find(__)!=-1:' with an re.search... where the re is defined as: restricted = re.compile(r|\..join([ __, func_, f_, im_, tb_, gi_, throw])) and the test becomes simply: if restricted.search(name): All the above attempts will be blocked this way. Any other disallow- sub-strings to add to the list above? And thanks a lot Daniel, need to find a way to get somebeer over to ya... ;-) mario -- http://mail.python.org/mailman/listinfo/python-list
Re: Start multiple listening servers in one file
Thomas W wrote: I`m working on a django-project where I`m using the awsome pyftpdlib for ftpserver-functionality. I also have a simple worker deamon running in the background, but not listening to any port. How can I start all of these processes on one file? Tried using subprocess and popen but that resulted in an eternal loop starting the servers over and over until all resources were used, then crash. Any hint on how to do this would be highly appreciated. Do you mean that your script is invoking itself? If yes, then could you pass something on the commandline to say you're not the initial instance, so don't invoke yourself and then check that? -- http://mail.python.org/mailman/listinfo/python-list
Re: Python 3: range objects cannot be sliced
On Jan 16, 5:45 pm, Alan G Isaac alan.is...@gmail.com wrote: Is the behavior below expected? Documented? (The error msg is misleading.) Thanks, Alan Isaac x = range(20) s = slice(None,None,2) x[s] Traceback (most recent call last): File stdin, line 1, in module TypeError: sequence index must be integer, not 'slice' Well, it has the same behaviour as the iterator returned by xrange in Python 2.X - so expected I guess. The error message is also the same in Python 2.X. Michael Foord -- http://www.ironpythoninaction.com/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Python 3: range objects cannot be sliced
Alan G Isaac alan.is...@gmail.com writes: x = range(20) s = slice(None,None,2) x[s] Traceback (most recent call last): File stdin, line 1, in module TypeError: sequence index must be integer, not 'slice' range is an iterator now. Try itertools.islice. -- http://mail.python.org/mailman/listinfo/python-list
Re: List comprehension - NameError: name '_[1]' is not defined ?
mario ruggier mario.rugg...@gmail.com writes: All the above attempts will be blocked this way. Any other disallow- sub-strings to add to the list above? I think what you are trying to do is fundamentally hopeless. You might look at web.py (http://webpy.org) for another approach, that puts a complete interpreter for a Python-like language into the template engine. -- http://mail.python.org/mailman/listinfo/python-list
Re: Integrating awk in Python
Am Freitag, 16. Januar 2009 13:02:59 schrieb Alfons Nonell-Canals: Hello, I'm developing a software package using python. I've programmed all necessary tools but I have to use other stuff from other people. Most of these external scripts are developed using awk. At the beggining I thought to translate them and program them in python but I prefer to avoid it because it means a lot of work and I should do it after each new version of this external stuff. I would like to integrate them into my python code. I know I can call them using the system environment but it is slower than if I call them inside the package. So you've tried system(), and it didn't meet your requirements? I know it is possible with C, What is possible with C? do you have experience on integrate awk into python calling these awk scripts from python? Just like in C, you can call them directory using fork/exec to eliminate the shell spawned by system(), but the difference in time is probably going to be negligible. If you're not able to meet your timing requirements using os.system(), then I suspect it's the awk programs that are too slow. I'd probably use the subprocess module to avoid the shell for security reasons. First, get it working. Then, after you've established that the program isn't meeting the timing specification _measure_ where the time is going. It's silly trying optimize the part of the program that's only taking up 1% of the execution time. Premature optimization... -- Grant Edwards grante Yow! They collapsed at ... like nuns in the visi.comstreet ... they had no teen appeal! -- http://mail.python.org/mailman/listinfo/python-list
minidom, drilling down to a low node in one line?
Hello, I hope this isn't completely redundant... I'm working with an example found of parsing XML with xml.dom.minidom and am having some issues getting a node down three levels. Here is the tutorial: http://diveintopython.org/xml_processing/parsing_xml.html Given the XML: _ ?xml version=1.0 ? grammar ref id=bit p0/p p1/p /ref /grammar _ How do I address the textNode.data that = 0? The only way I figured out is to recursively childNode from the parsed down (as following the guide). Is there no way to simply address the item by something along the lines of: _ xmldoc = minidom.parse(example.xml) xmldoc.getElementsByTagName(grammar:ref:p:) _ Any input or direction is appreciated. Thanks! Matt -- http://mail.python.org/mailman/listinfo/python-list
Re: Python 3: range objects cannot be sliced
On 1/16/2009 1:15 PM Paul Rubin apparently wrote: range is an iterator now. Try itertools.islice. Well yes, it behaves like xrange did. But (also like xrange) it supports indexing. (!) So why not slicing? I expected this (to keep it functionally more similar to the old range). Alan Isaac -- http://mail.python.org/mailman/listinfo/python-list
Re: Python 3: range objects cannot be sliced
Alan G Isaac schrieb: On 1/16/2009 1:15 PM Paul Rubin apparently wrote: range is an iterator now. Try itertools.islice. Well yes, it behaves like xrange did. But (also like xrange) it supports indexing. (!) So why not slicing? I expected this (to keep it functionally more similar to the old range). The old range function returned a list. If you need the old functionality you can use list(range(...))[]. Why do you want to slice a range anyway? The range type supports a start, stop and step argument. Christian -- http://mail.python.org/mailman/listinfo/python-list
Re: why o/p is different ???
On Jan 15, 1:34 pm, asit lipu...@gmail.com wrote: I recently faced a peculiar o/p. My objective is to remove the command name(my script name) from sys.argv[0]. I coded like this import urllib import sys print \n\n\t\tlipun4u[at]gmail[dot]com print \t\t apppath = sys.argv[0].split(/) appname = apppath[len(apppath)-1] print appname if len(sys.argv) not in [2,3]: print Usage : + appname + url [options] print e.g. : + appname + www.google.com--verbose print \n\t[option] print \t\t--verbose/-V for verbose output print \t\t-r for recursive scan sys.exit(1) site = appname.replace(http://,;).rsplit(/,1)[0] site = http://; + site.lower() print site It showed the required o/p in the IDLE here is the o/p lipun4u[at]gmail[dot]com linkscan.py Usage : linkscan.py url [options] e.g. : linkscan.pywww.google.com--verbose [option] --verbose/-V for verbose output -r for recursive scan Traceback (most recent call last): File I:/Python26/linkscan.py, line 18, in module sys.exit(1) SystemExit: 1 But in command prompt the o/p is still faulty lipun4u[at]gmail[dot]com I:\Python26\linkscan.py Usage : I:\Python26\linkscan.py url [options] e.g. : I:\Python26\linkscan.pywww.google.com--verbose [option] --verbose/-V for verbose output -r for recursive scan I:\Python26 regards asit dhal Of course the pragmatic approach is just to include appname = 'linkscan.py' at the top of the document. I agree apppath might change (because you copied the program to different places, different bin directory on different machine), but there is no reason linkscan.py should change. And if you have to change the invoking name, sometimes it might be more useful for users to know the REAL name of the program (probably the user friendly version, e.g. Link Scanner or Link Scanner 1.0), instead of the name of the script it is run from (without the apppath). It is trivial for human user to guess where the script is located and what the appname is from the full apppath (path+name) -- http://mail.python.org/mailman/listinfo/python-list
FileCookieJar has not attribute _self_load
I am trying to make a testing script to load/save cookies to a file with FileCookieJar, but it results in this error: FileCookieJar has not attribute _self_load This is my script: import urllib.request, urllib.parse,http.cookiejar url=http://localhost/test.php; cs=http.cookiejar.FileCookieJar() cs.load(cookies.txt,ignore_discard=False, ignore_expires=False) opener=urllib.request.build_opener(urllib.request.HTTPCookieProcessor (cs)) y=opener.open(url) print(y.read()) Thanks for helping. -- http://mail.python.org/mailman/listinfo/python-list
Differences between class and function decorator
Hello everyone, I rewrote an example someone posted here recently from: def print_method_name(method): def new_meth(*args, **kwargs): print method.func_name return method(*args, **kwargs) return new_meth @print_method_name def f2(): pass f2() f2 ..to: class MyMethod(object): def __init__(self, func): self.name = func.func_name self.func = func def __call__(self): print self.name return self.func @MyMethod def f(): pass f() f function f at 0x017CDA70 Note that function decorator returned None, while class decorator returned function. Why the difference in behavior? After all, print_method_name decorator also returns a function (well it's a new function but still a function)? Regards, mk -- http://mail.python.org/mailman/listinfo/python-list
Re: Differences between class and function decorator
mk mrk...@gmail.com wrote: Note that function decorator returned None, while class decorator returned function. Why the difference in behavior? After all, print_method_name decorator also returns a function (well it's a new function but still a function)? That would be because the function decorator returns the result of calling the function whereas your class decorator simply returns the function without calling it. -- http://mail.python.org/mailman/listinfo/python-list
Re: Does Python really follow its philosophy of Readability counts?
On Jan 16, 5:22 am, Steve Holden st...@holdenweb.com wrote: Russ P. wrote: [...] I spent *way* too much time on that post. I really need to quit spending my time refuting the baloney that passes for wisdom here. He who cannot ignore baloney is doomed to refute it. regards Steve -- Steve Holden+1 571 484 6266 +1 800 494 3119 Holden Web LLC http://www.holdenweb.com/ Yeah, and I should really learn to leave off those little zingers. If Mr. D weren't obviously an intelligent person and a Python expert, I wouldn't care what he writes. I just think that he, along with a few others here, love Python so much that they refuse to recognize its limitations. It's an easy trap to fall into. -- http://mail.python.org/mailman/listinfo/python-list
Re: are there some special about '\x1a' symbol
Steve Holden st...@holdenweb.com writes: Unknown wrote: On 2009-01-12, John Machin sjmac...@lexicon.net wrote: I didn't think your question was stupid. Stupid was (a) CP/M recording file size as number of 128-byte sectors, forcing the use of an in-band EOF marker for text files (b) MS continuing to regard Ctrl-Z as an EOF decades after people stopped writing Ctrl-Z at the end of text files. I believe that feature was inherited by CP/M from DEC OSes (RSX-11 or RSTS-11). AFAICT, all of CP/M's file I/O API (including the FCB) was lifted almost directly from DEC's PDP-11 stuff, which probably copied it from PDP-8 stuff. Perhaps in the early 60's somebody at DEC had a reason. The really interesting thing is that we're still suffering because of it 40+ years later. I suspect this is probably a leftover from some paper tape data formats, when it was easier to detect the end of a file with a sentinel byte than it was to detect run-off as end of file. It could easily date back to the PDP-8. I think it was a reasonable way for CP/M to work. It's a nice simple interface for reading and writing files: you always read and write from/to a fixed 128-byte buffer. Allowing files to be arbitrary-length byte sequences would have made the system calls more complicated, and it would also have needed another byte in the on-disk file control block (so 7.3 filenames rather than 8.3, or some other compromise). For CP/M programs, it's hard to see what the gain would have been; it's easy to design a binary file format so that it doesn't matter whether or not there's junk on the end, and CP/M didn't have a tradition of storing data in 'plain text' files (for good reasons of disk space). It certainly is a shame that we didn't leave all this behind when MS/DOS 2 appeared, though. -M- -- http://mail.python.org/mailman/listinfo/python-list
Re: Lazy List Generator Problem
For those interested in the Sieve of Eratosthenes, have a look at:
http://www.cs.hmc.edu/~oneill/papers/Sieve-JFP.pdf
The examples in the paper are in Haskell, but I have been
corresponding with the author who provided this Python version:
def sieve():
innersieve = sieve()
prevsquare = 1
table = {}
i = 2
while True:
if (table.has_key(i)):
prime = table[i]
del(table[i])
next = i+prime
while next in table:
next = next + prime
table[next] = prime
else:
yield i
if i prevsquare:
j = innersieve.next()
prevsquare = j * j
table[prevsquare] = j
i = i + 1
Only of 65056 bytes (less than 1/16 MB) of heap is used when
calculating the millionth prime. It is also very fast but can be even
further optimized using a wheel as described in the paper. FWIW I was
so intrigued I went off to learn Haskell just so I could follow the
paper properly.
--
http://mail.python.org/mailman/listinfo/python-list
Re: English-like Python
On 16 Jan, 05:42, Chris Rebert c...@rebertia.com wrote: On Thu, Jan 15, 2009 at 5:02 PM, The Music Guy music...@alphaios.net wrote: Just out of curiousity, have there been any attempts to make a version of Python that looks like actual English text? [...] Does the name AppleScript mean anything to you? ;-) [quoting myself on the subject] The big advantage of AppleScript syntax is that it makes it easy to get a broad idea of what an existing AppleScript does, even if you don't know the AppleScript language in particular or programming in general. The big disadvantage of AppleScript syntax is that it makes it very difficult to form an accurate understanding of how it actually does it. For example, is 'foo bar' a property name, a constant name, a command name, a command name followed by a property/constant/variable name, or something else again? With more conventional language syntaxes, you have the opposite situation: in order to make any sense at all of an existing script, you first have to learn to read the syntax and know some basic programming. OTOH, once you're past that initial hurdle, it's easier to understand exactly what makes it tick, e.g. x.foo_bar is a property name, :foo_bar is a constant, foo_bar() is a command, foo(bar) is a command name followed by a variable name, and so on. The upshot of this is that AppleScript has a lower barrier to entry but higher cost of use compared to other languages. It's a trade-off, but one that probably fits quite well with the needs of many AppleScripters, who write relatively small programs on an irregular basis. A high cost of entry will be harder to justify if you don't actually use the language very often. OTOH, if you write large programs on a daily basis then what matters most is long-term productivity, and you'll recoup the time taken to learn a language fairly quickly by comparison. ... If you really want an end-user language that has the legibility of already-familiar natural languages while retaining all the precision provided by traditional programming syntax and adding a lot of much- needed interactive help and guidance, I think the best approach would be to go with an 'intelligent' structure editor a-la Scratch or Alice, rather than 'dumb' character-based source code as found in Python, AppleScript, Inform-7, C, et-al. See: http://scratch.mit.edu/ http://www.alice.org/ If you eliminate the need for syntax to describe structure, you can present programs in whatever way suits users best - be it English words in coloured blocks, or traditional brackets and braces. Plus it becomes an awful lot easier to help and correct novice users as they put together their first programs - much as the original Mac GUI provided much better input guidance and error prevention over previous DOS-style command lines. HTH has -- Control AppleScriptable applications from Python, Ruby and ObjC: http://appscript.sourceforge.net -- http://mail.python.org/mailman/listinfo/python-list
Re: English-like Python
alex23 wrote: On Jan 16, 5:39 pm, Erik Max Francis m...@alcyone.com wrote: Inform 7 has some interesting ideas, but I think the general problem with English-like programming language systems is that once you get into the nitty gritty details, you end up having to know exactly the right things to type, This has always been my impression of Inform 7. I have a lot of respect for what they've set out to achieve but English isn't exactly known for its lack of ambiguity. This is great for literature but not so helpful for programming. which ultimately get just as complicated as a more traditional programming language syntax. And much more verbose, as well. Agreed. I, too, am impressed with what the authors tried to do for Inform 7. -- Erik Max Francis m...@alcyone.com http://www.alcyone.com/max/ San Jose, CA, USA 37 18 N 121 57 W AIM, Y!M erikmaxfrancis Laws are silent in time of war. -- Cicero -- http://mail.python.org/mailman/listinfo/python-list
Re: Python 3: range objects cannot be sliced
It is documented: http://docs.python.org/3.0/library/stdtypes.html#sequence-types-str-bytes-bytearray-list-tuple-range -- http://mail.python.org/mailman/listinfo/python-list
Class decorator with argument
Hello,
I wrote this class decorator with argument:
class ChangeDoc(object):
def __init__(self, docstring):
self.docstring = docstring
def __call__(self, func):
func.__doc__ = self.docstring
return func
It seems to work:
@ChangeDoc(bulba)
def f():
pass
f.__doc__
'bulba'
Can someone please debug my reasoning if it's incorrect?
1. First, the decorator @ChangeDoc('bulba') instantiates with
__init__(self, 'bulba'), to some class instance, let's call it _decor.
2. Then _decor's __call__ method is called with function f as argument,
changing the docstring and returning the changed f object, like f =
_decor(f) .
Am I missing smth important / potentially useful in typical real-world
applications in that picture?
Regards,
mk
--
http://mail.python.org/mailman/listinfo/python-list
Finding the full path of an executable
Is there a portable way to find the full path of a filename that would be called by os.execvp()? Thanks, Michael Hoffman -- http://mail.python.org/mailman/listinfo/python-list
tuple methods: documentation missing
http://docs.python.org/3.0/library/stdtypes.html#sequence-types-str-bytes-bytearray-list-tuple-range I see no mention of the tuple methods? Right after the paragraph Most sequence types support the following operations. it seems appropriate to have one stating Most sequence types support the following methods: index() and count(). Alan Isaac -- http://mail.python.org/mailman/listinfo/python-list
*Advanced* Python book?
Hello everyone, I looked for it I swear, but just can't find it. Most Python books seem to focus on examples of how to call functions from standard library. I don't need that, I have online Python documentation for that. I mean really advanced mental gymnastics, like gory details of how Python objects operate, how to exploit its dynamic capabilities, dos and donts with particular Python objects, advanced tricks, everything from chained decorators to metaprogramming. Dive Into Python comes closest to this ideal from what I have found, but still not far enough. Anybody found such holy grail? Regards, mk -- http://mail.python.org/mailman/listinfo/python-list
