Re: Input() in Python3
On Fri, Apr 22, 2011 at 4:49 PM, Chris Angelico wrote: > U NO. NO NO NO. What if someone enters "os.exit()" as their > number? You shouldn't eval() unchecked user input! Whoops, I meant sys.exit() - but you probably knew that already. ChrisA -- http://mail.python.org/mailman/listinfo/python-list
Re: Input() in Python3
On Fri, Apr 22, 2011 at 4:22 PM, harrismh777 wrote:
> now we get this for input():
>
> raw_input("prompt>") --> string
I would have to say that the 2.x behaviour of input() is a mistake
that's being corrected in 3.x. With a simple name like input(), it
should do something simple and straightforward - not eval() the
expression.
> to: a = eval(input("enter a number > "))
U NO. NO NO NO. What if someone enters "os.exit()" as their
number? You shouldn't eval() unchecked user input!
Chris Angelico
--
http://mail.python.org/mailman/listinfo/python-list
Re: learnpython.org - an online interactive Python tutorial
Heiko Wundram wrote: The difference between strong typing and weak typing is best described by: Python 2.6.5 (r265:79063, Jun 12 2010, 17:07:01) [GCC 4.3.4 20090804 (release) 1] on cygwin Type "help", "copyright", "credits" or "license" for more information. >>> 1+'2' Traceback (most recent call last): File "", line 1, in TypeError: unsupported operand type(s) for +: 'int' and 'str' >>> Yes. And you have managed to point out a serious flaw in the overall logic and consistency of Python, IMHO. Strings should auto-type-promote to numbers if appropriate. This behavior should occur in input() as well. If a 'number' string is entered and can be converted to a Python number (whatever I mean by that at the moment) then the string should be converted to a number (int or float as appropriate) and the input() should return a reference to the number type ( a value ); otherwise, input() should return the string entered, or throw a type error. If an operation like (+) is used to add 1 + '1' then the string should be converted to int and the addition should take place, returning a reference to object int (2). My feelings about this are strongly influenced by my experiences with the REXX language on IBM's SAA systems--- OS/2 and VM/CMS. In REXX everything is a string... everything. If a string just happens to be a REXX number, then it can be manipulated as you might expect for a number. Neither here, nor there... just that I believe Python could take advantage of the "Python Number" concept and provide for auto-type casting of string to number (int or float) as appropriate if the string meets the Python Number requirements. Just an idea... again, probably got beat up long before my time, I'm guessing... kind regards, m harris -- http://mail.python.org/mailman/listinfo/python-list
Re: dictionary size changed during iteration
On 4/20/2011 5:52 AM, Laszlo Nagy wrote: Given this iterator: class SomeIterableObject(object): def __iter__(self): ukeys = self.updates.keys() for key in ukeys: if self.updates.has_key(key): yield self.updates[key] for rec in self.inserts: yield rec How can I get this exception: RuntimeError: dictionary changed size during iteration It is true that self.updates is being changed during the iteration. But I have created the "ukeys" variable solely to prevent this kind of error. Here is a proof of correctness: I think we need to see some more code here. Also, what version of Python are you running? http://docs.python.org/library/stdtypes.html says "keys() Return a copy of the dictionary’s list of keys." So "ukeys" should be a unique list, not some part of self.updates or a generator. At least in Python 2.6, keys() does return a unique list. Each call to "keys()" returns a new list object unconnected to the dictionary from which the keys were extracted. But someone may have decided in a later version to return a generator, as an optimization. Did that happen? John Nagle -- http://mail.python.org/mailman/listinfo/python-list
Input() in Python3
My interactive scripts are giving errors on the input(). I discovered
another fairly significant change in Python3, as discussed in PEP 3111.
I was a little flabbergasted to discover that input() was proposed to be
removed 'totally' from 3000. Of course I agree with PEP 3111 and am
thankful that input() is still a built-in. doh.
The problem is that the behavior was significantly changed, again,
causing existing code to break un-necessarily. So, input() used to be
equivalent to:
eval(raw_input("prompt>")) --> value
now we get this for input():
raw_input("prompt>") --> string
I'm not whining or anything, just wondering why? Could someone enlighten
me please?
Anyway, it looks like the best fix for 2.x --> 3.x code changes:
change:a = input("enter a number > ")
to:a = eval(input("enter a number > "))
Again, this is just another example where leaving the advertised
interface alone would have made more sense... unless of course, I'm
missing something important here.
kind regards,
m harris
--
http://mail.python.org/mailman/listinfo/python-list
Re: Teaching Python
Westley Martínez wrote: But really, hack >has always been a negative term. It's original definition is chopping, >breaking down, kind of like chopping down the security on someone elses >computer. Now I don't know where the term originally came from, but the >definition the media uses is quite a fair use. Not so much... ... the term hacker was coined at the MIT lab back in the days of the PDP-10 /11. We can thank RMS, and friends. http://stallman.org/cgi-bin/showpage.cgi?path=/articles/on-hacking.html&term=hacking&type=norm&case=0 RMS coined the term "Cracker" for the pejorative use. Hackers cause no harm; ever. Hackers are elegant ethical people who love the craft for the sake of the craft and the beauty of their art. Hackers do have a disdain for "Herbert," (if you're a Trek-ie you know what I mean)...and hackers love to taunt Herbert... Herbert...! Herbert...! Herbert...! /\ / \ Hackers are free and insist on freedom. Hackers would rather count on their fingers than be forced to use proprietary closed systems and software. Hackers have no use for IBM, nor Microsoft. (nor google) I am and forever will be a joyful hacker :) PS The media is clueless... (Herbert... Herbert... Herbert...) -- http://mail.python.org/mailman/listinfo/python-list
Re: Teaching Python
MRAB wrote: A computer hacker doesn't write the requirements of the software or draw Jackson Structured Programming diagrams, etc, but just thinks about what's needed and starts writing the code. Very close... ... hackers don't necessarily care what something was designed to do, only what can be done with it... ... hackers love to push the envelope, playfully explore the full range of possibilities, and especially they delight to think outside the box (outside the frameworks of conformity and mediocrity)... ... hackers are philosophers and poets, and often musicians. Hackers write code because its beautiful, not because they're paid for it... hackers are can-do people who don't give a flying rip when they're told they can't ! ... yeah, watch me. :) kind regards, m harris -- http://mail.python.org/mailman/listinfo/python-list
Re: Teaching Python
MRAB wrote: That's a cowboy coder. A cowboy coder is someone who's bad at coding, a hacker is someone who's good at it. A hacker is someone who loves to code and doesn't really care whether anyone else thinks they're really at it or not... although, yes, they generally are *very* good at it... :) -- http://mail.python.org/mailman/listinfo/python-list
Re: Closing generators
On 4/21/2011 9:14 PM, Thomas Rachel wrote: Hi folks, it is possible to close a generator. That is (among others) for the following case: I run a for loop over the iterator, but then I break it. Now I can leave the generator to the GC (which is AFAI have been told a thing which I should not do), or I can clean up myself. That is very rarely necessary. generator.close was added so that one could tell the generator to close anything opened within the generator, such as a file, that needs to be explicitly closed. Example: for i in g: if i is not None: g.close() return i When returning from the function, g, if local, should disappear. -- Terry Jan Reedy -- http://mail.python.org/mailman/listinfo/python-list
Re: Snowball to Python compiler
On 4/21/2011 8:25 PM, Paul Rubin wrote: Matt Chaput writes: I'm looking for some code that will take a Snowball program and compile it into a Python script. Or, less ideally, a Snowball interpreter written in Python. (http://snowball.tartarus.org/) Anyone heard of such a thing? I never saw snowball before, it looks kind of interesting, and it looks like it already has a way to compile to C. If you're using it for IR on any scale, you're surely much better off using the C routines with a C API wrapper, If the C routines are in a shared library, you should be able to write the interface in Python with ctypes. than translating snowball to Python, which will be dog slow to interpret. -- Terry Jan Reedy -- http://mail.python.org/mailman/listinfo/python-list
Re: learnpython.org - an online interactive Python tutorial
On Thu, Apr 21, 2011 at 8:20 PM, Dan Stromberg wrote: > > On Thu, Apr 21, 2011 at 9:13 AM, MRAB wrote: > >> On 21/04/2011 15:14, Westley Martínez wrote: >> >>> On Thu, Apr 21, 2011 at 05:19:29PM +1000, Chris Angelico wrote: >>> On Thu, Apr 21, 2011 at 5:10 PM, Algis Kabaila wrote: > False: Python IS strongly typed, without doubt (though the > variables are not explicitly declared.) > Strongly duck-typed though. If I create a class that has all the right members, it can simultaneously be a file, an iterable, a database, and probably even a web browser if it feels like it. Is that strong typing or not? Chris Angelico -- http://mail.python.org/mailman/listinfo/python-list >>> >>> It's strong typing. Python does not implicitly convert types. Weak >>> typing is >>> when I can do 1 + "1" and get 2. >>> >> >> It could be argued that it does implicit convert for some numeric >> types, eg int to float when needed. > > > Yes, it'll silently promote int to float, int to Decimal, and also almost > anything can be used in a Boolean context. No other exceptions to strong > typing come to mind... > > > -- > http://mail.python.org/mailman/listinfo/python-list > > Hi: Really nice site, keep it going -- Still Going Strong!!! -- http://mail.python.org/mailman/listinfo/python-list
Re: A question about Python Classes
On Thu, 21 Apr 2011 19:00:08 +0100, MRAB wrote: >>> How can HomeHandler call foo() when I never created an instance of >>> BaseHandler? >> >> But you created one! >> > No, he didn't, he created an instance of HomeHandler. > >> test is an instance of HomeHandler, which is a subclass of BaseHandler, >> so test is also an instance of BaseHandler. >> > test isn't really an instance of BaseHandler, it's an instance of > HomeHandler, which is a subclass of BaseHandler. Which *also* makes it an instance of BaseHandler. You are a human being, which also makes you a mammal. It would be *wrong* to say that you're not a mammal, just because you're a human being. But to answer the Original Poster's question... you don't need a formal BaseHandler instance because that's how inheritance is designed to work. Each class knows its own parent classes, and when you call test.foo(), Python walks the chain of: instance instance's class each of the parent class(es) (if any) looking for a match for foo, and then calls it appropriately. This is called inheritance: HomeHandler inherits behaviour from BaseHandler. (The details are a little more complex than the sketch above, but broadly equivalent.) -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: Argument count mismatch
On Thu, 21 Apr 2011 12:33:09 -0700, RVince wrote:
> I am getting the following:
>
> Error - : cmseditorlinemethod() takes
> exactly 2 arguments (1 given)
>
> When I make the following call:
>
> http://localhost/eligibility/cmseditorlinemethod/474724434
That's not a call, that's a URL. It's also a link to localhost, which is
*your* computer and not visible to us.
How about actually showing us the *actual call* you make? Cut and paste
the line of code that calls cmseditorlinemethod, showing the arguments.
My *guess* is that you're calling it without providing any arguments:
instance.cmseditorlinemethod()
Python automatically injects the `self` argument, but it requires two:
self and ssn:
> def cmseditorlinemethod(self, ssn):
[...]
An alternative explanation: you don't use `self` in the body of
cmseditorlinemethod. Possibly cmseditorlinemethod is actually a stand-
alone function rather than a method, and you are calling it like this:
cmseditorlinemethod(ssn)
but you have mistakenly declared the function to take two arguments.
Really, the error message is quite explicit in your problem: you have one
argument given, but two arguments are required. The only subtlety is that
for method calls, the `self` argument is automatically provided rather
than manually, but once you've learned that quirk of Python, what else do
you need to know to solve this problem?
By the way, I know this is unsolicited advice, but I'm going to give it
anyway. Look at your function:
def cmseditorlinemethod(self, ssn):
c.details = Session.query(MSPResponse).filter(
MSPResponse.beneficiaryssn == ssn).all()
content = render('/cmseditorline.mako')
return content
It looks to me like this function relies on no fewer than three global
variables, two that you read from and one which you write to:
c
Session
MSPResponse
This is almost certainly poor design. Using global state is almost always
harmful and should be avoided.
(I don't include `render` in this, as using global functions is normally
harmless.)
http://c2.com/cgi/wiki?GlobalVariablesAreBad
--
Steven
--
http://mail.python.org/mailman/listinfo/python-list
Re: Vectors
Algis Kabaila wrote: the Vector3 class is available without any prefix euclid: import euclid v = Vector3(111.., 222.2, 333.3) Doesn't work that way for me: Python 2.7 (r27:82500, Oct 15 2010, 21:14:33) [GCC 4.2.1 (Apple Inc. build 5664)] on darwin Type "help", "copyright", "credits" or "license" for more information. >>> import euclid >>> Vector3 Traceback (most recent call last): File "", line 1, in NameError: name 'Vector3' is not defined Are you sure you hadn't previously done 'from euclid import Vector3' or 'from euclid import *' in that session? -- Greg -- http://mail.python.org/mailman/listinfo/python-list
Re: Teaching Python
On Fri, Apr 22, 2011 at 01:25:00AM +0100, MRAB wrote: > On 21/04/2011 23:36, Westley Martínez wrote: > >On Thu, Apr 21, 2011 at 05:11:32PM +0100, MRAB wrote: > >>On 21/04/2011 14:58, Westley Martínez wrote: > >>>On Thu, Apr 21, 2011 at 06:02:08AM +0200, Stefan Behnel wrote: > Ben Finney, 20.04.2011 02:06: > >Dan Stromberg writes: > > > >>On Tue, Apr 19, 2011 at 4:03 PM, geremy condra wrote: > >>>When you say 'hacking', you mean ? > >> > >>Presumably he meant the real meaning of the word, not what the press > >>made up and ran with. > > > >To be fair, the press already had its own pejorative meaning of “hack” > >before the engineering and computing term > > Not anywhere outside of the English language that I'm aware of, > though. In German, it's a computing-only term that's used in both > contexts by those who understand why the pointer is moving over the > screen when moving the mouse, and almost exclusively in a bad > context by those who write news paper articles (and, consequently, > by those who innocently read them). > > Stefan > > -- > http://mail.python.org/mailman/listinfo/python-list > >>> > >>>O Lord, I'd hope we'd be speaking for English here. But really, hack > >>>has always been a negative term. It's original definition is chopping, > >>>breaking down, kind of like chopping down the security on someone elses > >>>computer. Now I don't know where the term originally came from, but the > >>>definition the media uses is quite a fair use. Why should we call > >>>ourselves hackers anyways? I don't smoke. I'm no different from anyone > >>>else, I just happen to know a lot about computers. Should we call > >>>people who know a lot about the economy hackers, too, or perhaps we > >>>should call them economists > >> > >>As I understand it, "hacking" is about not doing the job "properly". > >>When trying to make something, a hacker will use the equivalent of duct > >>tape to hold things together. > >> > >>A computer hacker doesn't write the requirements of the software or > >>draw Jackson Structured Programming diagrams, etc, but just thinks > >>about what's needed and starts writing the code. > > > >That's a cowboy coder. > > A cowboy coder is someone who's bad at coding, a hacker is someone > who's good at it. Wrong, sir! Wrong! Cowboys are awesome. -- http://mail.python.org/mailman/listinfo/python-list
Closing generators
Hi folks, it is possible to close a generator. That is (among others) for the following case: I run a for loop over the iterator, but then I break it. Now I can leave the generator to the GC (which is AFAI have been told a thing which I should not do), or I can clean up myself. Example: for i in g: if i is not None: g.close() return i or better try: for i in g: if i is not None: return i finally: g.close() or even better with contextlib.closing(g): for i in g: if i is not None: return i How do you do that in this case - do you just drop the generator, or do you close it? (Beware of exceptions which could happen!) Till now, I used to just drop it, but now I am thinking about if it is good style or not... Another question: AFAICT generator.close() was introduced at about the same time as the with statement. Was a matching context manager deliberately left away, or just forgotten? It is fine to work with "with" on a file or other closable object - why not on a generator, without contextlib.closing()? TIA, Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: learnpython.org - an online interactive Python tutorial
On Thu, Apr 21, 2011 at 9:13 AM, MRAB wrote: > On 21/04/2011 15:14, Westley Martínez wrote: > >> On Thu, Apr 21, 2011 at 05:19:29PM +1000, Chris Angelico wrote: >> >>> On Thu, Apr 21, 2011 at 5:10 PM, Algis Kabaila >>> wrote: >>> False: Python IS strongly typed, without doubt (though the variables are not explicitly declared.) >>> >>> Strongly duck-typed though. If I create a class that has all the right >>> members, it can simultaneously be a file, an iterable, a database, and >>> probably even a web browser if it feels like it. Is that strong typing >>> or not? >>> >>> Chris Angelico >>> -- >>> http://mail.python.org/mailman/listinfo/python-list >>> >> >> It's strong typing. Python does not implicitly convert types. Weak >> typing is >> when I can do 1 + "1" and get 2. >> > > It could be argued that it does implicit convert for some numeric > types, eg int to float when needed. Yes, it'll silently promote int to float, int to Decimal, and also almost anything can be used in a Boolean context. No other exceptions to strong typing come to mind... -- http://mail.python.org/mailman/listinfo/python-list
Re: About threads in python
On Thu, Apr 21, 2011 at 6:19 AM, dutche wrote: > Hi folks, how are ya? > > Here's the thing...I had to make a program with threads and after > finished, I found some posts and articles in Google about Python and > threads, raising the question about if it really implements thread > programming or not, because of GIL and the way Python needs to lock > some objects. > http://wiki.python.org/moin/Concurrency Either all or nearly all Python implementations have threading, but for some implementations and some workloads, multithreading is not as effective as multiprocessing. Don't try to program in Python as though it's whatever other language you're coming from. It's better to learn each language's own strengths and weaknesses, and work with them rather than against them. EG: You shouldn't do list processing in FORTRAN, even if you were once a Lisp programmer. There are equivalent ways of achieving the same goals in FORTRAN, if you're willing to give up your Lisp influence though. -- http://mail.python.org/mailman/listinfo/python-list
Re: is there a difference between one line and many lines
On Thu, 21 Apr 2011 14:35:25 +0200, Peter Otten wrote: > Steven D'Aprano wrote: > >> but: >> > a = 1001; b = 10001; a is b >> False > > I would hope so ;) Doh! >> The point is that Python is free to re-use immutable objects, or not >> re- use them, as it sees fit. > > Indeed, and I even found a Python implementation on my harddisk that > does what you intended to show: > > $ ipy > IronPython 1.1.1 (1.1.1) on .NET 2.0.50727.1433 Copyright (c) Microsoft > Corporation. All rights reserved. a = 1001; b = 1001; a is b > False Much better, thank you :) -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: Snowball to Python compiler
Matt Chaput writes: > I'm looking for some code that will take a Snowball program and > compile it into a Python script. Or, less ideally, a Snowball > interpreter written in Python. > > (http://snowball.tartarus.org/) > > Anyone heard of such a thing? I never saw snowball before, it looks kind of interesting, and it looks like it already has a way to compile to C. If you're using it for IR on any scale, you're surely much better off using the C routines with a C API wrapper, than translating snowball to Python, which will be dog slow to interpret. -- http://mail.python.org/mailman/listinfo/python-list
Re: Teaching Python
On 21/04/2011 23:36, Westley Martínez wrote: On Thu, Apr 21, 2011 at 05:11:32PM +0100, MRAB wrote: On 21/04/2011 14:58, Westley Martínez wrote: On Thu, Apr 21, 2011 at 06:02:08AM +0200, Stefan Behnel wrote: Ben Finney, 20.04.2011 02:06: Dan Stromberg writes: On Tue, Apr 19, 2011 at 4:03 PM, geremy condra wrote: When you say 'hacking', you mean ? Presumably he meant the real meaning of the word, not what the press made up and ran with. To be fair, the press already had its own pejorative meaning of “hack” before the engineering and computing term Not anywhere outside of the English language that I'm aware of, though. In German, it's a computing-only term that's used in both contexts by those who understand why the pointer is moving over the screen when moving the mouse, and almost exclusively in a bad context by those who write news paper articles (and, consequently, by those who innocently read them). Stefan -- http://mail.python.org/mailman/listinfo/python-list O Lord, I'd hope we'd be speaking for English here. But really, hack has always been a negative term. It's original definition is chopping, breaking down, kind of like chopping down the security on someone elses computer. Now I don't know where the term originally came from, but the definition the media uses is quite a fair use. Why should we call ourselves hackers anyways? I don't smoke. I'm no different from anyone else, I just happen to know a lot about computers. Should we call people who know a lot about the economy hackers, too, or perhaps we should call them economists As I understand it, "hacking" is about not doing the job "properly". When trying to make something, a hacker will use the equivalent of duct tape to hold things together. A computer hacker doesn't write the requirements of the software or draw Jackson Structured Programming diagrams, etc, but just thinks about what's needed and starts writing the code. That's a cowboy coder. A cowboy coder is someone who's bad at coding, a hacker is someone who's good at it. -- http://mail.python.org/mailman/listinfo/python-list
Re: Snowball to Python compiler
A third (more-than-) possible solution: google("python snowball");
the first page of results has at least 3 hits referring to Python
wrappers for Snowball.
There are quite a few wrappers for the C-compiled snowball stemmers, but
I'm looking for a pure-Python solution. It doesn't seem like there is
such a thing, but I figured I'd take a shot here before I think about
doing it myself :/
Matt
--
http://mail.python.org/mailman/listinfo/python-list
Re: Snowball to Python compiler
On Friday, April 22, 2011 8:05:37 AM UTC+10, Matt Chaput wrote:
> I'm looking for some code that will take a Snowball program and compile
> it into a Python script. Or, less ideally, a Snowball interpreter
> written in Python.
>
> (http://snowball.tartarus.org/)
If anyone has done such things they are not advertising them in the usual
places.
A third (more-than-) possible solution: google("python snowball"); the first
page of results has at least 3 hits referring to Python wrappers for Snowball.
--
http://mail.python.org/mailman/listinfo/python-list
Re: Argument count mismatch
On Thu, Apr 21, 2011 at 12:33:09PM -0700, RVince wrote:
> I am getting the following:
>
> Error - : cmseditorlinemethod() takes
> exactly 2 arguments (1 given)
>
> When I make the following call:
>
> http://localhost/eligibility/cmseditorlinemethod/474724434
>
> Which invokes:
>
> def cmseditorlinemethod(self, ssn):
> c.details =
> Session.query(MSPResponse).filter(MSPResponse.beneficiaryssn ==
> ssn).all()
> content = render('/cmseditorline.mako')
> return content
>
> Can anyone tell me what the mismatch is in the number of my parameters
> based on this? Thanks, RVince
There's no way to see that link without knowing a domainname or IP.
localhost only works locally, go figure, but regardless I'd suspect that
you need to give two arguments instead of one, considering that's what
the error message said.
--
http://mail.python.org/mailman/listinfo/python-list
Re: Teaching Python
On Thu, Apr 21, 2011 at 05:11:32PM +0100, MRAB wrote: > On 21/04/2011 14:58, Westley Martínez wrote: > >On Thu, Apr 21, 2011 at 06:02:08AM +0200, Stefan Behnel wrote: > >>Ben Finney, 20.04.2011 02:06: > >>>Dan Stromberg writes: > >>> > On Tue, Apr 19, 2011 at 4:03 PM, geremy condra wrote: > >When you say 'hacking', you mean ? > > Presumably he meant the real meaning of the word, not what the press > made up and ran with. > >>> > >>>To be fair, the press already had its own pejorative meaning of “hack” > >>>before the engineering and computing term > >> > >>Not anywhere outside of the English language that I'm aware of, > >>though. In German, it's a computing-only term that's used in both > >>contexts by those who understand why the pointer is moving over the > >>screen when moving the mouse, and almost exclusively in a bad > >>context by those who write news paper articles (and, consequently, > >>by those who innocently read them). > >> > >>Stefan > >> > >>-- > >>http://mail.python.org/mailman/listinfo/python-list > > > >O Lord, I'd hope we'd be speaking for English here. But really, hack > >has always been a negative term. It's original definition is chopping, > >breaking down, kind of like chopping down the security on someone elses > >computer. Now I don't know where the term originally came from, but the > >definition the media uses is quite a fair use. Why should we call > >ourselves hackers anyways? I don't smoke. I'm no different from anyone > >else, I just happen to know a lot about computers. Should we call > >people who know a lot about the economy hackers, too, or perhaps we > >should call them economists > > As I understand it, "hacking" is about not doing the job "properly". > When trying to make something, a hacker will use the equivalent of duct > tape to hold things together. > > A computer hacker doesn't write the requirements of the software or > draw Jackson Structured Programming diagrams, etc, but just thinks > about what's needed and starts writing the code. That's a cowboy coder. -- http://mail.python.org/mailman/listinfo/python-list
Snowball to Python compiler
On the slim chance that (a) somebody worked on something like this but never uploaded it to PyPI, and (b) the person who did (a) or heard about it is reading this list ;) -- I'm looking for some code that will take a Snowball program and compile it into a Python script. Or, less ideally, a Snowball interpreter written in Python. (http://snowball.tartarus.org/) Anyone heard of such a thing? Thanks! Matt -- http://mail.python.org/mailman/listinfo/python-list
Re: Argument count mismatch
In RVince
writes:
> def cmseditorlinemethod(self, ssn):
> c.details =
> Session.query(MSPResponse).filter(MSPResponse.beneficiaryssn ==
> ssn).all()
> content = render('/cmseditorline.mako')
> return content
Is cmseditorlinemethod() a member of a class? The presence of the "self"
parameter suggests that it is, but your code omits this detail.
--
John Gordon A is for Amy, who fell down the stairs
gor...@panix.com B is for Basil, assaulted by bears
-- Edward Gorey, "The Gashlycrumb Tinies"
--
http://mail.python.org/mailman/listinfo/python-list
Re: Finding empty columns. Is there a faster way?
On Apr 21, 5:40 pm, nn wrote:
> time head -100 myfile >/dev/null
>
> real 0m4.57s
> user 0m3.81s
> sys 0m0.74s
>
> time ./repnullsalt.py '|' myfile
> 0 1 Null columns:
> 11, 20, 21, 22, 23, 24, 25, 26, 27, 30, 31, 33, 45, 50, 68
>
> real 1m28.94s
> user 1m28.11s
> sys 0m0.72s
>
> import sys
> def main():
> with open(sys.argv[2],'rb') as inf:
> limit = sys.argv[3] if len(sys.argv)>3 else 1
> dlm = sys.argv[1].encode('latin1')
> nulls = [x==b'' for x in next(inf)[:-1].split(dlm)]
> enum = enumerate
> split = bytes.split
> out = sys.stdout
> prn = print
> for j, r in enum(inf):
> if j%100==0:
> prn(j//100,end=' ')
> out.flush()
> if j//100>=limit:
> break
> for i, cur in enum(split(r[:-1],dlm)):
> nulls[i] |= cur==b''
> print('Null columns:')
> print(', '.join(str(i+1) for i,val in enumerate(nulls) if val))
>
> if not (len(sys.argv)>2):
> sys.exit("Usage: "+sys.argv[0]+
> " ")
>
> main()
What's with the aliasing enumerate and print??? And on heavy disk IO I
can hardly see that name lookups are going to be any problem at all?
And why the time stats with /dev/null ???
I'd probably go for something like:
import csv
with open('somefile') as fin:
nulls = set()
for row in csv.reader(fin, delimiter='|'):
nulls.update(idx for idx,val in enumerate(row, start=1) if not
val)
print 'nulls =', sorted(nulls)
hth
Jon
--
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Re: Argument count mismatch
On Fri, Apr 22, 2011 at 5:33 AM, RVince wrote: > I am getting the following: > > Error - : cmseditorlinemethod() takes > exactly 2 arguments (1 given) > > When I make the following call: > > http://localhost/eligibility/cmseditorlinemethod/474724434 > > Which invokes: > > def cmseditorlinemethod(self, ssn): You're doing an HTTP request that ultimately is supposed to translate into a method call. The problem appears to be somewhere in between those; what system are you using to handle HTTP (web) requests, and how does it translate a URL into a method call? As a side point, if it takes a piece of the URL and looks it up, unchecked, as a member name, this is a rather dodgy practice. I hope you have a whitelist of legal method names. Chris Angelico -- http://mail.python.org/mailman/listinfo/python-list
Re: Argument count mismatch
On Donnerstag 21 April 2011, RVince wrote: > When I make the following call: > > http://localhost/eligibility/cmseditorlinemethod/474724434 broken link - I have no /eligilibity on my localhost -- Wolfgang -- http://mail.python.org/mailman/listinfo/python-list
Argument count mismatch
I am getting the following:
Error - : cmseditorlinemethod() takes
exactly 2 arguments (1 given)
When I make the following call:
http://localhost/eligibility/cmseditorlinemethod/474724434
Which invokes:
def cmseditorlinemethod(self, ssn):
c.details =
Session.query(MSPResponse).filter(MSPResponse.beneficiaryssn ==
ssn).all()
content = render('/cmseditorline.mako')
return content
Can anyone tell me what the mismatch is in the number of my parameters
based on this? Thanks, RVince
--
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Re: Remote Connection
On 20-04-11 05:26, ray wrote: The speech commands will scripted in Python. Dragonfly is the Python project to coordinate this but does not address connectivity. So I am wondering if there have been any Python projects to address the connectivity. ray I'm not quite sure what you want exactly, but maybe one or more of the available Python rpc modules/libraries can be used to your needs? They offer communication between Python processes on separate machines, but may not be entirely suitable for your needs of audio data transfer. Still, they should be able to transfer chunks of audio data in some way to a remote machine. Some protocols are better suited for this than others. Some libraries that may be useful perhaps: Pyro (see http://pypi.python.org/pypi/Pyro4/ ) xmlrpclib (part of the standard library) or perhaps even httplib or ftplib ? Hth, Irmen. -- http://mail.python.org/mailman/listinfo/python-list
Re: Groups in regular expressions don't repeat as expected
2011/4/20 MRAB : > On 20/04/2011 20:20, John Nagle wrote: >> >> Here's something that surprised me about Python regular expressions. >> >> ... > You should take a look at the regex module on PyPI. :-) > -- > Ah well... sorry for possibly destroying the point and the aha! effect ... vbr -- http://mail.python.org/mailman/listinfo/python-list
Re: A question about Python Classes
chad wrote: Let's say I have the following class BaseHandler: def foo(self): print "Hello" class HomeHandler(BaseHandler): pass Then I do the following... test = HomeHandler() test.foo() How can HomeHandler call foo() when I never created an instance of BaseHandler? You don't need to create an instance of BaseHandler. You have the class, Python knows you have the class -- Python will look there if the subclasses lack an attribute. ~Ethan~ -- http://mail.python.org/mailman/listinfo/python-list
Re: A question about Python Classes
On 21/04/2011 18:12, Pascal J. Bourguignon wrote: chad writes: Let's say I have the following class BaseHandler: def foo(self): print "Hello" class HomeHandler(BaseHandler): pass Then I do the following... test = HomeHandler() test.foo() How can HomeHandler call foo() when I never created an instance of BaseHandler? But you created one! No, he didn't, he created an instance of HomeHandler. test is an instance of HomeHandler, which is a subclass of BaseHandler, so test is also an instance of BaseHandler. test isn't really an instance of BaseHandler, it's an instance of HomeHandler, which is a subclass of BaseHandler. If you do this: class BaseHandler(object): def foo(self): print "Hello" class HomeHandler(BaseHandler): pass test = HomeHandler() then you'll find: >>> isinstance(test, BaseHandler) True but: >>> type(test) -- http://mail.python.org/mailman/listinfo/python-list
Re: A question about Python Classes
On 4/21/2011 11:43 AM, chad wrote: Let's say I have the following class BaseHandler: def foo(self): print "Hello" class HomeHandler(BaseHandler): pass Then I do the following... test = HomeHandler() test.foo() How can HomeHandler call foo() when I never created an instance of BaseHandler? When you ask for an attribute of an instance of a class, the attribute lookup first looks at the instance; if not there, then the class; if not there, then superclass(es); and so on back to class 'object'. >>> class C(): pass >>> c=C() >>> c.__hash__ # how does this happen when C has no __hash__ method? >>> C.__hash__ # C inherits __hash__ and other special methods from 'object' >>> hash(c) 1035101 # uses the default, inherited method. Most syntactic operations and builtins are ultimately converted to a special method call, often inherited like this. In fact, c.x is converted to object.__getattribute__(c, 'x'). >>> object.__getattribute__(c, '__hash__') You do need to understand inheritance. On the other hand, do not worry about behind-the-scenes implementation details like 'method_wrapper' and 'slot_wrapper' classes, which may be CPython specific. -- Terry Jan Reedy -- http://mail.python.org/mailman/listinfo/python-list
Re: Python 3.2 on CentOS 5.6 & compatibility concerns
On 4/21/2011 8:02 AM, Rob McGillivray wrote: Hi All, Does anyone know if it is ‘safe’ to install Python 3.2 on CentOS? By ‘safe’ I mean not breaking the existing base Python 2.4.x installation upon which various CentOS/RHEL services (like yum) depend. Will the ‘make install’ install 3.2 in parallel with the existing 2.x installation, or break it? I’m new to Python and OSS, but the little I’ve read indicates that this could be a major risk. I have read on this list that there is a 'make altinstall' for *nix to avoid problems with the 'base' install. (2.4, really? that is ancient!). -- Terry Jan Reedy -- http://mail.python.org/mailman/listinfo/python-list
Re: A question about Python Classes
chad writes:
> Let's say I have the following
>
> class BaseHandler:
> def foo(self):
> print "Hello"
>
> class HomeHandler(BaseHandler):
> pass
>
>
> Then I do the following...
>
> test = HomeHandler()
> test.foo()
>
> How can HomeHandler call foo() when I never created an instance of
> BaseHandler?
But you created one!
test is an instance of HomeHandler, which is a subclass of BaseHandler,
so test is also an instance of BaseHandler.
A subclass represents a subset of the instances of its super class.
--
__Pascal Bourguignon__ http://www.informatimago.com/
A bad day in () is better than a good day in {}.
--
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Re: A question about Python Classes
On Apr 21, 2011 12:55 PM, "chad" wrote: > > On Apr 21, 9:30 am, Jean-Michel Pichavant > wrote: > > chad wrote: > > > Let's say I have the following > > > > > class BaseHandler: > > > def foo(self): > > > print "Hello" > > > > > class HomeHandler(BaseHandler): > > > pass > > > > > Then I do the following... > > > > > test = HomeHandler() > > > test.foo() > > > > > How can HomeHandler call foo() when I never created an instance of > > > BaseHandler? > > > > > Chad > > > > you did, test is an instance of BaseHandler. > > > > > isinstance(test, HomeHandler) > > < True > > > > > isinstance(test, BaseHandler) > > < True > > > > So it just just creates an instance of every class that it inherits? > > Chad No. it is an instance of every class it inherits. It's called inheritance because it inherits the attributes and methods of the parent class > -- > http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
Re: A question about Python Classes
On Apr 21, 9:30 am, Jean-Michel Pichavant wrote: > chad wrote: > > Let's say I have the following > > > class BaseHandler: > > def foo(self): > > print "Hello" > > > class HomeHandler(BaseHandler): > > pass > > > Then I do the following... > > > test = HomeHandler() > > test.foo() > > > How can HomeHandler call foo() when I never created an instance of > > BaseHandler? > > > Chad > > you did, test is an instance of BaseHandler. > > > isinstance(test, HomeHandler) > < True > > > isinstance(test, BaseHandler) > < True > So it just just creates an instance of every class that it inherits? Chad -- http://mail.python.org/mailman/listinfo/python-list
Finding empty columns. Is there a faster way?
time head -100 myfile >/dev/null
real0m4.57s
user0m3.81s
sys 0m0.74s
time ./repnullsalt.py '|' myfile
0 1 Null columns:
11, 20, 21, 22, 23, 24, 25, 26, 27, 30, 31, 33, 45, 50, 68
real1m28.94s
user1m28.11s
sys 0m0.72s
import sys
def main():
with open(sys.argv[2],'rb') as inf:
limit = sys.argv[3] if len(sys.argv)>3 else 1
dlm = sys.argv[1].encode('latin1')
nulls = [x==b'' for x in next(inf)[:-1].split(dlm)]
enum = enumerate
split = bytes.split
out = sys.stdout
prn = print
for j, r in enum(inf):
if j%100==0:
prn(j//100,end=' ')
out.flush()
if j//100>=limit:
break
for i, cur in enum(split(r[:-1],dlm)):
nulls[i] |= cur==b''
print('Null columns:')
print(', '.join(str(i+1) for i,val in enumerate(nulls) if val))
if not (len(sys.argv)>2):
sys.exit("Usage: "+sys.argv[0]+
" ")
main()
--
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Re: A question about Python Classes
chad wrote: Let's say I have the following class BaseHandler: def foo(self): print "Hello" class HomeHandler(BaseHandler): pass Then I do the following... test = HomeHandler() test.foo() How can HomeHandler call foo() when I never created an instance of BaseHandler? Chad you did, test is an instance of BaseHandler. > isinstance(test, HomeHandler) < True > isinstance(test, BaseHandler) < True JM -- http://mail.python.org/mailman/listinfo/python-list
shared dictionary of dictionaries with Manager
Hi all, I was trying to share a dictionary of dictionaries of arrays with Manager from multiprocessing. Without multiprocessing the code works perfectly, but with the current example the last print does not show the correct result. Any hint? Thanks, Darío Suárez#!/usr/local/bin/python2.7 import sys import warnings from multiprocessing import Pool, Value, Array, Manager N_PROCESSES = 8 def f(results, key): results[key]['d'][3].append(1) def main(): pool = Pool(processes=N_PROCESSES) manager = Manager() results = manager.dict() for key in ['k', 'kk']: results[key] = dict([(key2, [[] for i in range(4)]) for key2 in ['d', 'dd']]) res = [ pool.apply_async(f, key) for key in ['k'] ] map(lambda x: x.wait(), res) print results['k'] print results['k']['d'] print results['k']['d'][3] if __name__ == "__main__": main() -- http://mail.python.org/mailman/listinfo/python-list
Re: A question about Python Classes
You did: >>> class BaseHandler: ... def foo(self): ... print "Hello" ... >>> class HomerHandler(BaseHandler): ... pass ... >>> test = HomerHandler() >>> test.foo() Hello >>> isinstance(test, BaseHandler) True >>> isinstance(test, HomerHandler) True >>> You could say test is a "BaseHandler of type HomerHandler" 2011/4/21 chad > Let's say I have the following > > class BaseHandler: >def foo(self): >print "Hello" > > class HomeHandler(BaseHandler): >pass > > > Then I do the following... > > test = HomeHandler() > test.foo() > > How can HomeHandler call foo() when I never created an instance of > BaseHandler? > > Chad > -- > http://mail.python.org/mailman/listinfo/python-list > -- http://mail.python.org/mailman/listinfo/python-list
Re: learnpython.org - an online interactive Python tutorial
On 21/04/2011 15:14, Westley Martínez wrote: On Thu, Apr 21, 2011 at 05:19:29PM +1000, Chris Angelico wrote: On Thu, Apr 21, 2011 at 5:10 PM, Algis Kabaila wrote: False: Python IS strongly typed, without doubt (though the variables are not explicitly declared.) Strongly duck-typed though. If I create a class that has all the right members, it can simultaneously be a file, an iterable, a database, and probably even a web browser if it feels like it. Is that strong typing or not? Chris Angelico -- http://mail.python.org/mailman/listinfo/python-list It's strong typing. Python does not implicitly convert types. Weak typing is when I can do 1 + "1" and get 2. It could be argued that it does implicit convert for some numeric types, eg int to float when needed. -- http://mail.python.org/mailman/listinfo/python-list
Re: Teaching Python
On 21/04/2011 14:58, Westley Martínez wrote: On Thu, Apr 21, 2011 at 06:02:08AM +0200, Stefan Behnel wrote: Ben Finney, 20.04.2011 02:06: Dan Stromberg writes: On Tue, Apr 19, 2011 at 4:03 PM, geremy condra wrote: When you say 'hacking', you mean ? Presumably he meant the real meaning of the word, not what the press made up and ran with. To be fair, the press already had its own pejorative meaning of “hack” before the engineering and computing term Not anywhere outside of the English language that I'm aware of, though. In German, it's a computing-only term that's used in both contexts by those who understand why the pointer is moving over the screen when moving the mouse, and almost exclusively in a bad context by those who write news paper articles (and, consequently, by those who innocently read them). Stefan -- http://mail.python.org/mailman/listinfo/python-list O Lord, I'd hope we'd be speaking for English here. But really, hack has always been a negative term. It's original definition is chopping, breaking down, kind of like chopping down the security on someone elses computer. Now I don't know where the term originally came from, but the definition the media uses is quite a fair use. Why should we call ourselves hackers anyways? I don't smoke. I'm no different from anyone else, I just happen to know a lot about computers. Should we call people who know a lot about the economy hackers, too, or perhaps we should call them economists As I understand it, "hacking" is about not doing the job "properly". When trying to make something, a hacker will use the equivalent of duct tape to hold things together. A computer hacker doesn't write the requirements of the software or draw Jackson Structured Programming diagrams, etc, but just thinks about what's needed and starts writing the code. -- http://mail.python.org/mailman/listinfo/python-list
Re: How deal with the coding
On 21/04/2011 07:27, 1011_wxy wrote:
Dear All:
I got a coding problem when I use python to read html from web which is
encode with gb2312,
ater I insert the data I read from web into Oracle DB with coding gbk, I
found messy code by select from PL/SQL.
I tried the way ".encode('gbk','ignore')" before insert Oracle by using
cx_Oracle,but not effective.
How can I deal with the coding?
It's probably better to use UTF-8 wherever possible.
Decode to Unicode and work with Unicode strings.
Use UTF-8 when you want to store or transmit data.
Use another encoding _only_ if it's required by a legacy application (an
old application which requires that encoding.).
--
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A question about Python Classes
Let's say I have the following class BaseHandler: def foo(self): print "Hello" class HomeHandler(BaseHandler): pass Then I do the following... test = HomeHandler() test.foo() How can HomeHandler call foo() when I never created an instance of BaseHandler? Chad -- http://mail.python.org/mailman/listinfo/python-list
Python-URL! - weekly Python news and links (Apr 21)
QOTW: "Python is a pragmatic language, so all the rules come pre- broken." - Mel http://groups.google.com/group/comp.lang.python/msg/208face4a8e00062 Look! In the sky! It's a SciPy demonstration! It's a business! No, it's ForecastWatch: http://goo.gl/AvzqZ EuroPython 2011: Firenze, 20-26 June 2011: http://ep2011.europython.eu/ Python Software Foundation is collecting for a special project: http://tinyurl.com/PSF-donation Jesse Noller explains the PSF: http://bit.ly/e1j7JE Do you *realize* how much you get with Plone, for free? http://goo.gl/fb/KRodb [Django and many other Python outposts also are wonderful, in their own ways, of course.] Everything Python-related you want is probably one or two clicks away in these pages: Python.org's Python Language Website is the traditional center of Pythonia http://www.python.org Notice especially the master FAQ http://www.python.org/doc/FAQ.html Just beginning with Python? This page is a great place to start: http://wiki.python.org/moin/BeginnersGuide/Programmers Planet Python: you want to visit there: http://planet.python.org But don't confuse it with Planet SciPy: http://planet.scipy.org And don't confuse *that* with SciPyTip, a high-quality daily (!) tip for the numerically-inclined: http://twitter.com/SciPyTip Python Insider is the official blog of the Python core development team: http://pyfound.blogspot.com/2011/03/python-dev-launches-python-insider-blog.html The Python Software Foundation (PSF) has replaced the Python Consortium as an independent nexus of activity. It has official responsibility for Python's development and maintenance. http://www.python.org/psf/ Among the ways you can support PSF is with a donation. http://www.python.org/psf/donations/ Keep up with the PSF at "Python Software Foundation News": http://pyfound.blogspot.com The Python Papers aims to publish "the efforts of Python enthusiasts": http://pythonpapers.org/ Doug Hellman's "Module of the week" is essential reading: http://www.doughellmann.com/PyMOTW/ comp.lang.python.announce announces new Python software. Be sure to scan this newsgroup weekly. http://groups.google.com/group/comp.lang.python.announce/topics Python411 indexes "podcasts ... to help people learn Python ..." Updates appear more-than-weekly: http://www.awaretek.com/python/index.html The Python Package Index catalogues packages. http://www.python.org/pypi/ Much of Python's real work takes place on Special-Interest Group mailing lists http://www.python.org/sigs/ Python Success Stories--from air-traffic control to on-line match-making--can inspire you or decision-makers to whom you're subject with a vision of what the language makes practical. http://www.pythonology.com/success The Summary of Python Tracker Issues is an automatically generated report summarizing new bugs, closed ones, and patch submissions. http://search.gmane.org/?author=status%40bugs.python.org&group=gmane.comp.python.devel&sort=date nullege is an interesting search Web application, with the intelligence to distinguish between Python code and comments. It provides what appear to be relevant results, and demands neither Java nor CSS be enabled: http://www.nullege.com Although unmaintained since 2002, the Cetus collection of Python hyperlinks retains a few gems. http://www.cetus-links.org/oo_python.html Python FAQTS http://python.faqts.com/ The Cookbook is a collaborative effort to capture useful and interesting recipes: http://code.activestate.com/recipes/langs/python/ Many Python conferences around the world are in preparation. Watch this space for links to them. Among several Python-oriented RSS/RDF feeds available, see: http://www.python.org/channews.rdf For more, see: http://www.syndic8.com/feedlist.php?ShowMatch=python&ShowStatus=all The old Python "To-Do List" now lives principally in a SourceForge reincarnation. http://sourceforge.net/tracker/?atid=355470&group_id=5470&func=browse http://www.python.org/dev/peps/pep-0042/ del.icio.us presents an intriguing approach to reference commentary. It already aggregates quite a bit of Python intelligence. http://del.icio.us/tag/python At least one of the Python magazines is explicitly multilingual: http://www.python.org/ar/ PythonWare complemented the digest you're reading with the marvelous daily python url. While it's now ... dormant, it still has plenty of interesting reading. http://www.pythonware.com/daily Python articles regularly appear at IBM DeveloperWorks: http://w
Re: Problem receiving UDP broadcast packets.
On 2011-04-21, Dan Stromberg wrote: > On Wed, Apr 20, 2011 at 7:21 AM, Grant Edwards > wrote: >> On 2011-04-20, Dan Stromberg wrote: >>> On Tue, Apr 19, 2011 at 8:12 PM, Dan Stromberg wrote: I agree though that you're kind of pushing IP in a direction it wasn't intended to go. >>> >>> It just occurred to me: You might get some additional mileage out of >>> popping the network adapter into promiscuous mode. ?In fact, it Might >>> be necessary irrespective of the rest of your approach. >> >> The network adapter is already receiving all the packets I want to >> receive, so putting it into promiscuous mode would only increase the >> number of unwanted packets. > > I think tcpdump and tshark (was tethereal) will put the interface into > promiscuous mode so it can see more traffic; It can (and by default does). I was using "-p" so it didn't. > on OSF/1 (Tru64), we had > to do this manually for said programs to see all that was possible > (barring the presence of a switch not repeating packets the way > routers and hubs would). * The packets were being sent to MAC address ff:ff:ff:ff:ff:ff, so the NIC does not have to be in promiscuous mode to receive them. * tcpdump saw them even when it doesn't put the NIC in promiscuous mode. * The kernel was seeing the packets because it was logging them as martians and discarding them (something I didn't notice until later). * Turning off reverse-path filtering in the TCP stack allowed the packets to be received as expected. -- Grant Edwards grant.b.edwardsYow! I was making donuts at and now I'm on a bus! gmail.com -- http://mail.python.org/mailman/listinfo/python-list
Re: is there a difference between one line and many lines
On Thu, Apr 21, 2011 at 02:38:52AM -0700, vino19 wrote: > Hello, I'm a newbie. > What's the defference between > > >>>a=-6; b=-6; a is b > >>>True > > and > > >>>a=-6 > >>>b=-6 > >>>a is b > >>>False > > ? > -- > http://mail.python.org/mailman/listinfo/python-list Depends on how the interpreter was implemented. -- http://mail.python.org/mailman/listinfo/python-list
Re: learnpython.org - an online interactive Python tutorial
On Thu, Apr 21, 2011 at 05:19:29PM +1000, Chris Angelico wrote: > On Thu, Apr 21, 2011 at 5:10 PM, Algis Kabaila wrote: > > False: Python IS strongly typed, without doubt (though the > > variables are not explicitly declared.) > > Strongly duck-typed though. If I create a class that has all the right > members, it can simultaneously be a file, an iterable, a database, and > probably even a web browser if it feels like it. Is that strong typing > or not? > > Chris Angelico > -- > http://mail.python.org/mailman/listinfo/python-list It's strong typing. Python does not implicitly convert types. Weak typing is when I can do 1 + "1" and get 2. -- http://mail.python.org/mailman/listinfo/python-list
Re: Vectors
Andreas Tawn writes: > You might also want to consider http://code.google.com/p/pyeuclid/ Thanks, I was studying quaternions recently and had to use two packages to get some stuff done. And of course one of them used ass-backwards declaration for a quaternion and one didn't... -- http://mail.python.org/mailman/listinfo/python-list
Re: About threads in python
dutche, 21.04.2011 15:19: Here's the thing...I had to make a program with threads and after finished, I found some posts and articles in Google about Python and threads, raising the question about if it really implements thread programming or not, because of GIL and the way Python needs to lock some objects. I have now in my program something about 8 threads and each of them runs different code based on some directives, these codes relies sometimes in C api, using classes like zipfile and tarfile, and others relies only in python code. What do you mean by "relies sometimes on C api"? Do you mean that it uses binary modules, as opposed to Python modules? My question is about the efficiency of threads in python, does anybody has something to share? From your (rather unspecific) description, I gather that you are doing mostly I/O operations. Threading is an acceptable programming model for that, and Python supports it just fine. The GIL is usually released for I/O operations by the runtime, so if your program is I/O bound, you will get full threading concurrency. Stefan -- http://mail.python.org/mailman/listinfo/python-list
Re: Teaching Python
On Thu, Apr 21, 2011 at 06:02:08AM +0200, Stefan Behnel wrote: > Ben Finney, 20.04.2011 02:06: > >Dan Stromberg writes: > > > >>On Tue, Apr 19, 2011 at 4:03 PM, geremy condra wrote: > >>>When you say 'hacking', you mean ? > >> > >>Presumably he meant the real meaning of the word, not what the press > >>made up and ran with. > > > >To be fair, the press already had its own pejorative meaning of “hack” > >before the engineering and computing term > > Not anywhere outside of the English language that I'm aware of, > though. In German, it's a computing-only term that's used in both > contexts by those who understand why the pointer is moving over the > screen when moving the mouse, and almost exclusively in a bad > context by those who write news paper articles (and, consequently, > by those who innocently read them). > > Stefan > > -- > http://mail.python.org/mailman/listinfo/python-list O Lord, I'd hope we'd be speaking for English here. But really, hack has always been a negative term. It's original definition is chopping, breaking down, kind of like chopping down the security on someone elses computer. Now I don't know where the term originally came from, but the definition the media uses is quite a fair use. Why should we call ourselves hackers anyways? I don't smoke. I'm no different from anyone else, I just happen to know a lot about computers. Should we call people who know a lot about the economy hackers, too, or perhaps we should call them economists -- http://mail.python.org/mailman/listinfo/python-list
Re: Groups in regular expressions don't repeat as expected
2011/4/20 John Nagle :
> Here's something that surprised me about Python regular expressions.
>
krex = re.compile(r"^([a-z])+$")
s = "abcdef"
ms = krex.match(s)
ms.groups()
> ('f',)
>
>...
> "If a group is contained in a part of the pattern that matched multiple
> times, the last match is returned."
>
> That's kind of lame, though. I'd expect that there would be some way
> to retrieve all matches.
>
> John Nagle
> --
> http://mail.python.org/mailman/listinfo/python-list
Hi,
do you mean something like:
>>> import regex
>>> ms = regex.match(r"^([a-z])+$", "abcdef")
>>> ms.captures(1)
['a', 'b', 'c', 'd', 'e', 'f']
>>>
>>> help(ms.captures)
Help on built-in function captures:
captures(...)
captures([group1, ...]) --> list of strings or tuple of list of strings.
Return the captures of one or more subgroups of the match. If there is a
single argument, the result is a list of strings; if there are multiple
arguments, the result is a tuple of lists with one item per argument; if
there are no arguments, the captures of the whole match is returned. Group
0 is the whole match.
>>>
cf.
http://pypi.python.org/pypi/regex
hth,
vbr
--
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About threads in python
Hi folks, how are ya? Here's the thing...I had to make a program with threads and after finished, I found some posts and articles in Google about Python and threads, raising the question about if it really implements thread programming or not, because of GIL and the way Python needs to lock some objects. I have now in my program something about 8 threads and each of them runs different code based on some directives, these codes relies sometimes in C api, using classes like zipfile and tarfile, and others relies only in python code. My question is about the efficiency of threads in python, does anybody has something to share? Thanks in advance Eduardo -- http://mail.python.org/mailman/listinfo/python-list
Re: Groups in regular expressions don't repeat as expected
On 2011-04-20, John Nagle wrote:
> Findall does something a bit different. It returns a list of
> matches of the entire pattern, not repeats of groups within
> the pattern.
>
> Consider a regular expression for matching domain names:
>
> >>> kre = re.compile(r'^([a-zA-Z0-9\-]+)(?:\.([a-zA-Z0-9\-]+))+$')
> >>> s = 'www.example.com'
> >>> ms = kre.match(s)
> >>> ms.groups()
> ('www', 'com')
> >>> msall = kre.findall(s)
> >>> msall
> [('www', 'com')]
>
> This is just a simple example. But it illustrates an unnecessary
> limitation. The matcher can do the repeated matching; you just can't
> get the results out.
Thanks for the further explantion.
Assuming a fake API that returned multiple group matches as a
tuple:
>>? print(re.match(r"^([a-z])+$", "abcdef").groups())
(('a', 'b', 'c', 'd', 'e', 'f'),)
I was thinking of applying findall something like this, but you
have to make multiple calls:
>>> m = re.match(r"^[a-z]+$", s)
>>> if m:
... print(re.findall(r"[a-z]", m.group()))
...
['a', 'b', 'c', 'd', 'e', 'f']
I can see that getting really annoying. Is there a better way to
make multiple group matches accessible without adding a third
element type as a group element?
--
Neil Cerutti
--
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Re: is there a difference between one line and many lines
Steven D'Aprano wrote: > but: > a = 1001; b = 10001; a is b > False I would hope so ;) > The point is that Python is free to re-use immutable objects, or not re- > use them, as it sees fit. Indeed, and I even found a Python implementation on my harddisk that does what you intended to show: $ ipy IronPython 1.1.1 (1.1.1) on .NET 2.0.50727.1433 Copyright (c) Microsoft Corporation. All rights reserved. >>> a = 1001; b = 1001; a is b False -- http://mail.python.org/mailman/listinfo/python-list
Re: is there a difference between one line and many lines
On Thu, 21 Apr 2011 02:55:52 -0700, vino19 wrote: > Sure, I understand that "is" is not "==", cause "is" just compares > id(a)==id(b). > > I have a win32 CPython and the range of "singletons" is from -5 to 256 > on my machine. > > I am asking about what happens in Python interpreter? Why is there a > difference between running one line like "a=1;b=1" and two lines like > "a=1 \n b=1"? Does it decide to locate memory in different types depend > on a code? It's an implementation detail which is free to change from one version to the next. You can't rely on that behaviour, it could change at any time. You would have to study the source code of the exact version you are running, including any IDE if you are using an IDE, and see what it is doing. The point is that Python is free to re-use immutable objects, or not re- use them, as it sees fit. >>> sys.version '2.6.4 (r264:75706, Feb 1 2010, 13:33:07) \n[GCC 4.1.2 20070925 (Red Hat 4.1.2-27)]' >>> >>> >>> a = 1.23; b = 1.23; a is b True >>> c = 1.23 >>> c is a False but: >>> a = 1001; b = 10001; a is b False -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Python 3.2 on CentOS 5.6 & compatibility concerns
Hi All, Does anyone know if it is 'safe' to install Python 3.2 on CentOS? By 'safe' I mean not breaking the existing base Python 2.4.x installation upon which various CentOS/RHEL services (like yum) depend. Will the 'make install' install 3.2 in parallel with the existing 2.x installation, or break it? I'm new to Python and OSS, but the little I've read indicates that this could be a major risk. My goal is to setup a dev platform (currently CentOS/Wing IDE/Python 3.2) and learn Python 3.x (as apparently this is the future of the language), but at the same time I'm looking to use CentOS as the server platform for deployment, and so want to understand what's involved in managing Python installations/upgrades on this platform. Thanks in advance, Rob-- http://mail.python.org/mailman/listinfo/python-list
Re: Hello Sweet Friends
Dnia Thu, 21 Apr 2011 01:11:34 -0600, Ian Kelly napisał(a): > On Thu, Apr 21, 2011 at 12:28 AM, harrismh777 > wrote: >> I don't like SPAM with my eggs and ham... > > Nor do the rest of us, so please don't help it circumvent our spam > filters by reposting it. Hey, this is comp.lang.python, it's supposed to have at least some degree of Monty Python humour. KTB -- http://mail.python.org/mailman/listinfo/python-list
Reposting meat-like products [was Re: Hello Sweet Friends]
On Thu, 21 Apr 2011 01:11:34 -0600, Ian Kelly wrote: > On Thu, Apr 21, 2011 at 12:28 AM, harrismh777 > wrote: >> I don't like SPAM with my eggs and ham... > > Nor do the rest of us, so please don't help it circumvent our spam > filters by reposting it. Harris did cut out the URL though, so he gets credit for that. -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: is there a difference between one line and many lines
vino19 wrote: Sure, I understand that "is" is not "==", cause "is" just compares id(a)==id(b). I have a win32 CPython and the range of "singletons" is from -5 to 256 on my machine. I am asking about what happens in Python interpreter? Why is there a difference between running one line like "a=1;b=1" and two lines like "a=1 \n b=1"? Does it decide to locate memory in different types depend on a code? Thanks Probably, for optimisation purpose I guess. This is very implementation specific and as a newby, you should not care about such trivial details. The worst thing on earth you could do would be to code knowing that some values are singleton and take profit from it. Well, maybe coding in perl would be worse... JM -- http://mail.python.org/mailman/listinfo/python-list
Re: is there a difference between one line and many lines
vino19 wrote: > Hello, I'm a newbie. > What's the defference between > a=-6; b=-6; a is b True > > and > a=-6 b=-6 a is b False > > ? When you write it as a single line the assignments to a and b are part of the same compilation process, and as an optimization CPython's bytecode compiler looks for identical (integer, float, string) constants and uses the same object to represent them. To show that it's really the compilation not the number of lines: >>> exec """a = -6 ... b = -6 ... """ >>> a is b True -- http://mail.python.org/mailman/listinfo/python-list
Re: is there a difference between one line and many lines
Python 2.7.1 (downloaded from python.org a week ago) You see, if I save this to a file and then run from CMD: "python test1.py" the result will be the same: "True" When I use IDLE or IPython or DreamPie or maybe something else then result is not the same. So maybe as Chris Angelico said it is the IDLE(or Ipython) makes some optimization depend on a code style. -- http://mail.python.org/mailman/listinfo/python-list
Re: Feature suggestion -- return if true
Am 13.04.2011 01:06, schrieb Ethan Furman:
--> def func():
--> var1 = something()
--> var2 = something_else('this')
--> return? var1.hobgle(var2)
--> var3 = last_resort(var1)
--> return var3.wiglat(var2)
This makes me think of a decorator which can mimic the wantend behaviour:
def getfirst(f):
from functools import wraps
@wraps(f)
def func(*a, **k):
for i in f(*a, **k):
if i: return i
return func
# [BTW: a kind of "return decorator" would be nice here ;-)]
@getfirst
def func():
var1 = something()
var2 = something_else('this')
yield var1.hobgle(var2)
var3 = last_resort(var1)
yield var3.wiglat(var2)
yield "Even that did not work."
This has the advantage of being flexible about which condition to
evaluate: maybe the func does return tuples of which only the 2nd part
is relevant concerning the check. Then just do
def getfirst(f):
from functools import wraps
@wraps(f)
def func(*a, **k):
for i in f(*a, **k):
if i[1]: return i
return func
@getfirst
def func():
var1 = something()
var2 = something_else('this')
yield "first try", var1.hobgle(var2)
var3 = last_resort(var1)
yield "second try", var3.wiglat(var2)
yield "default value", "Even that did not work."
Disclaimer: Untested, but you should get the idea.
Thomas
--
http://mail.python.org/mailman/listinfo/python-list
Re: is there a difference between one line and many lines
Am 21.04.2011 11:59, schrieb Heiko Wundram: > Am 21.04.2011 11:55, schrieb vino19: >> I am asking about what happens in Python interpreter? Why is there a >> difference between running one line like "a=1;b=1" and two lines like "a=1 >> \n b=1"? Does it decide to locate memory in different types depend on a code? > > There is no difference between the two. > ... Erm, sorry, forget my post. I misread a=-6 as a-=6, etc... So: what Chris said. Anyway, there is semantically no difference between the two, and that stands. -- --- Heiko. -- http://mail.python.org/mailman/listinfo/python-list
Re: is there a difference between one line and many lines
On Thu, Apr 21, 2011 at 8:38 PM, vino19 wrote: > Hello, I'm a newbie. > What's the defference between >*skip* What is version of CPython? In 2.7.1 and 3.1.3 both versions return True, and moreover, are compiled to identical bytecode. >>> def test1(): ... a=-6; b=-6; c = a is b ... return c >>> def test3(): ... a=-6 ... b=-6 ... c = a is b ... return c >>> test1() True >>> test3() True >>> dis.dis(test1) 2 0 LOAD_CONST 1 (-6) 3 STORE_FAST 0 (a) 6 LOAD_CONST 1 (-6) 9 STORE_FAST 1 (b) 12 LOAD_FAST0 (a) 15 LOAD_FAST1 (b) 18 COMPARE_OP 8 (is) 21 STORE_FAST 2 (c) 3 24 LOAD_FAST2 (c) 27 RETURN_VALUE >>> dis.dis(test3) 2 0 LOAD_CONST 1 (-6) 3 STORE_FAST 0 (a) 3 6 LOAD_CONST 1 (-6) 9 STORE_FAST 1 (b) 4 12 LOAD_FAST0 (a) 15 LOAD_FAST1 (b) 18 COMPARE_OP 8 (is) 21 STORE_FAST 2 (c) 5 24 LOAD_FAST2 (c) 27 RETURN_VALUE So AFAIK, there is no difference for interpreter itself, its purely syntactic, and is compiled to exactly same bytecode. -- With best regards, Daniel Kluev -- http://mail.python.org/mailman/listinfo/python-list
Re: is there a difference between one line and many lines
On Thu, Apr 21, 2011 at 7:55 PM, vino19 wrote: > Sure, I understand that "is" is not "==", cause "is" just compares > id(a)==id(b). > > I have a win32 CPython and the range of "singletons" is from -5 to 256 on my > machine. > > I am asking about what happens in Python interpreter? Why is there a > difference between running one line like "a=1;b=1" and two lines like "a=1 \n > b=1"? Does it decide to locate memory in different types depend on a code? Ah okay! In that case, I'm guessing this is going to be an oddity of the IDLE system, because it's compiling each line separately. When you put it on a single line, it's saving some trouble by sharing the constant; when you do them separately, it doesn't optimize like that. Chris Angelico -- http://mail.python.org/mailman/listinfo/python-list
Re: is there a difference between one line and many lines
Am 21.04.2011 11:55, schrieb vino19: > I am asking about what happens in Python interpreter? Why is there a > difference between running one line like "a=1;b=1" and two lines like "a=1 \n > b=1"? Does it decide to locate memory in different types depend on a code? There is no difference between the two. You've not given the initializers for a/b in the two statement groups you showed, so that what Chris Angelico said is probably what's happening here (i.e.: in the first case, you stay in the singleton range, in the second case which builds on the first, you don't). -- --- Heiko. -- http://mail.python.org/mailman/listinfo/python-list
Re: is there a difference between one line and many lines
Sure, I understand that "is" is not "==", cause "is" just compares id(a)==id(b). I have a win32 CPython and the range of "singletons" is from -5 to 256 on my machine. I am asking about what happens in Python interpreter? Why is there a difference between running one line like "a=1;b=1" and two lines like "a=1 \n b=1"? Does it decide to locate memory in different types depend on a code? Thanks -- http://mail.python.org/mailman/listinfo/python-list
Re: is there a difference between one line and many lines
On Thu, Apr 21, 2011 at 7:38 PM, vino19 wrote: > Hello, I'm a newbie. > What's the defference between > a=-6; b=-6; a is b True > > and > a=-6 b=-6 a is b False You may want to use the == operator rather than "is". When you use "is", you're asking Python if the two variables are referencing the exact same object, but with ==, you're asking if they're equivalent. With integers from -1 to 99, Python keeps singletons, which means that your test would work if you used 6 instead of -6; but there's no guarantee of anything with the negatives. However, it doesn't matter whether the variables are pointing to the same object or not, if you use ==, because two different objects holding the number -6 will compare equal. Hope that clarifies it! Chris Angelico -- http://mail.python.org/mailman/listinfo/python-list
is there a difference between one line and many lines
Hello, I'm a newbie. What's the defference between >>>a=-6; b=-6; a is b >>>True and >>>a=-6 >>>b=-6 >>>a is b >>>False ? -- http://mail.python.org/mailman/listinfo/python-list
How deal with the coding
Dear All:
I got a coding problem when I use python to read html from web which is encode
with gb2312,
ater I insert the data I read from web into Oracle DB with coding gbk, I found
messy code by select from PL/SQL.
I tried the way ".encode('gbk','ignore')" before insert Oracle by using
cx_Oracle,but not effective.
How can I deal with the coding?
Thanks a lot
Best Regards
Kerry
2011-04-21--
http://mail.python.org/mailman/listinfo/python-list
Re: learnpython.org - an online interactive Python tutorial
Am 21.04.2011 09:19, schrieb Chris Angelico: > On Thu, Apr 21, 2011 at 5:10 PM, Algis Kabaila wrote: >> False: Python IS strongly typed, without doubt (though the >> variables are not explicitly declared.) > > Strongly duck-typed though. If I create a class that has all the right > members, it can simultaneously be a file, an iterable, a database, and > probably even a web browser if it feels like it. Is that strong typing > or not? Yes, that's strong typing, because your class only works in those contexts that you "explicitly" allow it to work in (through implementing an interface, be it an iterator, a file, etc.), independent of "duck-typing" (which is pretty much described by the term interface-based typing IMHO). The difference between strong typing and weak typing is best described by: Python 2.6.5 (r265:79063, Jun 12 2010, 17:07:01) [GCC 4.3.4 20090804 (release) 1] on cygwin Type "help", "copyright", "credits" or "license" for more information. >>> 1+'2' Traceback (most recent call last): File "", line 1, in TypeError: unsupported operand type(s) for +: 'int' and 'str' >>> which means that the interface for implementing "+" on the input types "int" and "str" isn't implemented (i.e., TypeError). Weakly typed languages allow this to work: modelnine@gj-celle ~ $ php 3 modelnine@gj-celle ~ $ through all kinds of type-casting magic, which isn't explicitly specified as interfaces on the objects (PHP also has integer and string objects) themselves. -- --- Heiko. -- http://mail.python.org/mailman/listinfo/python-list
Re: learnpython.org - an online interactive Python tutorial
Algis Kabaila wrote: [quote] Python is completely object oriented, and not "strongly typed" [/quote] False: Python IS strongly typed, without doubt (though the variables are not explicitly declared.) Playing the advocate for a moment here, this is something that I was confused about early on also... and frankly, you are both correct, but from different vantage points. Python IS strongly typed in that operations may only be applied to objects that support 'that' operation... numbers support (+) and also strings support (+) , although, the (+) does 'different' things depending on the object type. You might look at this as STRONGLY typed and you would be correct... however, you might look on this as weakly typed and you would still be correct... because why? Because, the programmer doesn't have to worry about the 'types' she is using ... the object based nature of the language and polymorphism come together so that the 'right thing' happens with (+) regardless of type... see? weakly typed... In C the programmer is always considering what 'type' is this thing... even testing for it... and C is considered by those programmers (yes, me ) as STRONGLY typed. The types must be declared ahead of time for sure, but that's not the point... the point is that the 'type' matters and must always be on the front lobes in thinking about logic. In Python much of the thinking about types is not even necessary.. for the most part... and by design. In this way of thinking the language is weakly typed... on the other hand, because the objects may be only manipulated by operations they support, this makes Python STRONGLY typed. Confused yet??? How one thinks about this depends on programming background, what is meant by 'type' and how the programmer differentiates thinking about types as variables versus objects. Having said all of that, I agree that Python should be classified as STRONGLY typed... and this classification should always come with an explanation ... especially to new advocates writing tutorials... kind regards, m harris -- http://mail.python.org/mailman/listinfo/python-list
Re: Vectors
On Thursday 21 April 2011 01:49:57 Andreas Tawn wrote: > > On Apr 20, 6:43 am, Andreas Tawn wrote: > > > > Algis Kabaila writes: > > > > > Are there any modules for vector algebra (three > > > > > dimensional vectors, vector addition, subtraction, > > > > > multiplication [scalar and vector]. Could you give > > > > > me a reference to such module? > > > > > > > > NumPy has array (and matrix) types with support for > > > > these basic operations you mention. See the tutorial > > > > athttp://numpy.scipy.org/ > > > > > > You might also want to > > > considerhttp://code.google.com/p/pyeuclid/ > > > > > > Cheers, > > > > > > Drea > > > > Pyeuclid docs don't mention dot or cross products. > > RJB > > http://partiallydisassembled.net/euclid/vector-classes.html#S > ECTION00222 > > Bottom of the page. > > Cheers, > > Drea Yes, pyeuclid had "cross" and "dot" product of vectors. I am impressed with it and curious how it works: the Vector3 class is available without any prefix euclid: import euclid v = Vector3(111.., 222.2, 333.3) works without requiring as in: v = euclid.Vector3( etc...) I am really intrigued by that. OTOH, I also am somewhat aprehensive about using something that affects the program writing after importing "euclid", without any need to explicitly refer to euclid. Looks rather risky to me. What does that do to the namespace? Thanks for bringing this to my attention. I confess that I would be hapier if euclid was accessible in a "standard" manner with prefix of module name for classes in the module. OldAl. -- Algis http://akabaila.pcug.org.au/StructuralAnalysis.pdf -- http://mail.python.org/mailman/listinfo/python-list
Re: learnpython.org - an online interactive Python tutorial
On Thu, Apr 21, 2011 at 5:10 PM, Algis Kabaila wrote: > False: Python IS strongly typed, without doubt (though the > variables are not explicitly declared.) Strongly duck-typed though. If I create a class that has all the right members, it can simultaneously be a file, an iterable, a database, and probably even a web browser if it feels like it. Is that strong typing or not? Chris Angelico -- http://mail.python.org/mailman/listinfo/python-list
Re: Hello Sweet Friends
On Thu, Apr 21, 2011 at 12:28 AM, harrismh777 wrote: > I don't like SPAM with my eggs and ham... Nor do the rest of us, so please don't help it circumvent our spam filters by reposting it. -- http://mail.python.org/mailman/listinfo/python-list
Re: learnpython.org - an online interactive Python tutorial
On Thursday 21 April 2011 03:15:50 Ron wrote: > Hey everyone. > > I've written an online interactive Python tutorial atop > Google App Engine: http://www.learnpython.org. > > All you need to do is log in using your Google account and > edit the wiki to add your tutorials. > > Read more on the website. > > Thanks for your help, and I would appreciate if you help me > spread the word, and give me feedback on the website. [quote] Python is completely object oriented, and not "strongly typed" [/quote] False: Python IS strongly typed, without doubt (though the variables are not explicitly declared.) Explicit declaration and strong typing are two completely differen things. If you are going to teach (and that is what tutorials are for), it is obligatory to learn first... OldAl. -- Algis http://akabaila.pcug.org.au/StructuralAnalysis.pdf -- http://mail.python.org/mailman/listinfo/python-list
