Re: PyLint results?
Others have answered most of your questions, I won't repeat the answers here, but only join the choir to stress that pylint needs tuning to your coding style. An obvious case is camelCaseMethodNames versus underscored_method_names, but there are also a lot of issues. The default pylint settings match Logilab's coding standards. The coding metrics were heavily inspired by Steve McConnell's Code Complete book, but the figures provided therein have been heavily downscaled to match for Python's expressivity (Code Complete deals mostly with C/C++/Java code). Le 21-04-2006, Michael [EMAIL PROTECTED] nous disait: 2) C: 0: Missing required attribute __revision__ What is this? Is that for CVS? I don't use CVS (we use SVN). I have not seen any sample code which includes this tag yet. But if I include __revision 1.0 somewhere in the code it will remove that warning? We generally have a __revision__ = '$Id$' statement at module top level, which gets replaced a check in time by CVS, which makes it easy to know who checked in the HEAD revision of the module. This behaviour can be emulated with subversion properties. 5) R:547:readDiscreteData: Too many branches (28/12) Python doesn't have the switch/case statements that C/C++ have. So I could have a large block if/elif/else statements. Is there any way to avoid that? 6) R:722:waitDiscretes: Too many local variables (38/15) That's new to me. What is wrong with too many local variables? Can anything be done to improve that besides having too many globals? For these two, I strongly recommend giving a look at Martin Fowler's Refactoring book (published by Addison Wesley). These are typical so called code smells which can be solved using for instance the Extract Method refactoring. Of course, it all depends on the kind of program you are working, and sometimes using intermediate variables helps understanding the code (by providing useful names, for instance). What pylint tells you is there could be an issue here, you should check. -- Alexandre Fayolle LOGILAB, Paris (France). http://www.logilab.com http://www.logilab.fr http://www.logilab.org -- http://mail.python.org/mailman/listinfo/python-list
PyLint results?
Hello: I ran the new pylint and my code and I had a few questions on why those are warnings or what I can do to fix them: 1) W: 0: Too many lines in module (1587) Why is 1587 considered too many lines? Would there be necessarily be an advantage to split it up into 2 or 3 files? Can I up the limit? 2) C: 0: Missing required attribute __revision__ What is this? Is that for CVS? I don't use CVS (we use SVN). I have not seen any sample code which includes this tag yet. But if I include __revision 1.0 somewhere in the code it will remove that warning? 3) W:230:readDiscreteData: Using the global statement What is wrong with using the global statement? I know the use of Globals should be discouraged, but often they can't be avoided. Suppose I have a constant. In C or C++, I could just use a #define and it would be known throughout the whole file. In Python, there isn't a similar construct, so rather than creating a large parameter list, of constants, I like to use globals. 4) W:261:getDiscreteData: Catch Exception What is wrong with that? 5) R:547:readDiscreteData: Too many branches (28/12) Python doesn't have the switch/case statements that C/C++ have. So I could have a large block if/elif/else statements. Is there any way to avoid that? 6) R:722:waitDiscretes: Too many local variables (38/15) That's new to me. What is wrong with too many local variables? Can anything be done to improve that besides having too many globals? 7) W:933:sendStringToSocket: Redefining name 'nPortNumber' from outer scope (line What is wrong with using the same variable name in a function that is used by its caller? 8) W:995:sendStringToSocket: Used builtin function 'map' Is that a problem? Plus many other warnings about my naming convention or unused variables which I will ignore at this time. I did find it to be a very useful too any how in cleaning up my code. I raised my code rate from about -8 to about +7. Thanks: Michael Yanowitz -- http://mail.python.org/mailman/listinfo/python-list
Re: PyLint results?
Michael Yanowitz escribió: Hello: I ran the new pylint and my code and I had a few questions on why those are warnings or what I can do to fix them: 2) C: 0: Missing required attribute __revision__ What is this? Is that for CVS? I don't use CVS (we use SVN). I have not seen any sample code which includes this tag yet. But if I include __revision 1.0 somewhere in the code it will remove that warning? try it and see what happens 3) W:230:readDiscreteData: Using the global statement What is wrong with using the global statement? I know the use of Globals should be discouraged, but often they can't be avoided. Suppose I have a constant. In C or C++, I could just use a #define and it would be known throughout the whole file. In Python, there isn't a similar construct, so rather than creating a large parameter list, of constants, I like to use globals. * define all your constants in a separate module constants.py, then: from constants import * * add the constants to __builtins__ __builtins__.constant_name = value this approach is a bit tricky 4) W:261:getDiscreteData: Catch Exception What is wrong with that? cause you're masquerading *all* exceptions, this could be potentially dangerous 6) R:722:waitDiscretes: Too many local variables (38/15) That's new to me. What is wrong with too many local variables? Can anything be done to improve that besides having too many globals? too many local variables probably means too complex function, split it in smaller functions -- http://mail.python.org/mailman/listinfo/python-list
Re: PyLint results?
* Michael Yanowitz wrote: I ran the new pylint and my code and I had a few questions on why those are warnings or what I can do to fix them: 1) W: 0: Too many lines in module (1587) Why is 1587 considered too many lines? Would there be necessarily be an advantage to split it up into 2 or 3 files? Can I up the limit? not necessarily. It might be considered bad style to put too much stuff into one module. This depends on the content. You can now raise the limit (which is 1000 lines by default) with the --max-module-lines command line option or using a config file (generate one with pylint --generate-rcfile, use it with pylint --rcfile=filename). Alternatively you can disable the message for this module by putting # pylint: disable-msg = Wid on the top (after the # -*- coding -*- line, if any). The new pylint allows for local disabling also such comments within the code. The id can you get if you enable them in the output via cmdline or config file. 2) C: 0: Missing required attribute __revision__ What is this? Is that for CVS? I don't use CVS (we use SVN). I have not seen any sample code which includes this tag yet. But if I include __revision 1.0 somewhere in the code it will remove that warning? yeah. But you can list these attributes in the config... ;-) 3) W:230:readDiscreteData: Using the global statement What is wrong with using the global statement? I know the use of Globals should be discouraged, but often they can't be avoided. Suppose I have a constant. In C or C++, I could just use a #define and it would be known throughout the whole file. In Python, there isn't a similar construct, so rather than creating a large parameter list, of constants, I like to use globals. Consider *writing* globals from inside a function as bad style. 4) W:261:getDiscreteData: Catch Exception What is wrong with that? Typically you do want be more specific, because Exception catches too much. 5) R:547:readDiscreteData: Too many branches (28/12) Python doesn't have the switch/case statements that C/C++ have. So I could have a large block if/elif/else statements. Is there any way to avoid that? Not always. But usually you can restructure your code better (Use more functions/methods, structure them semantically). 6) R:722:waitDiscretes: Too many local variables (38/15) That's new to me. What is wrong with too many local variables? Can anything be done to improve that besides having too many globals? One could loose the overview, I guess. 38 local variables are really a lot. Structure your code :) 7) W:933:sendStringToSocket: Redefining name 'nPortNumber' from outer scope (line What is wrong with using the same variable name in a function that is used by its caller? It might confuse someone else or you in half a year when reading the code again. 8) W:995:sendStringToSocket: Used builtin function 'map' Is that a problem? Not really. You might consider using list comprehensions, though. Plus many other warnings about my naming convention or unused variables which I will ignore at this time. I did find it to be a very useful too any how in cleaning up my code. I raised my code rate from about -8 to about +7. I personally find the code rate nonsense, YMMV ;-) Note that all messages from pylint should be taken as hints, not a final verdict. Think about them (you did, as you asked here ;-). Either correct or ignore them (typically done by locally or even globally disabling them). Do some fine-tuning using a config matching your own requirements. The defaults are, well, just defaults. nd -- die (eval q-qq[Just Another Perl Hacker ] ;-) # André Malo, http://pub.perlig.de/ # -- http://mail.python.org/mailman/listinfo/python-list
Re: PyLint results?
In [EMAIL PROTECTED], Michael Yanowitz wrote: 2) C: 0: Missing required attribute __revision__ What is this? Is that for CVS? I don't use CVS (we use SVN). I have not seen any sample code which includes this tag yet. But if I include __revision 1.0 somewhere in the code it will remove that warning? AFAIK that's a requirement at Logilab. They use the tool themselves. :-) 3) W:230:readDiscreteData: Using the global statement What is wrong with using the global statement? I know the use of Globals should be discouraged, but often they can't be avoided. I guess more often than you think. Suppose I have a constant. In C or C++, I could just use a #define and it would be known throughout the whole file. In Python, there isn't a similar construct, so rather than creating a large parameter list, of constants, I like to use globals. If they are constants then you don't rebind them from within functions or methods, right? Then you don't need ``global``. This works without problems:: ANSWER = 42 def spam(): print ANSWER 4) W:261:getDiscreteData: Catch Exception What is wrong with that? It catches *any* exception. For example `KeyboardInterrupt` which can lead to programs that can't be stopped with CTRL+C or `ZeroDivisionError` or `NameError` so programming errors are silenced. 5) R:547:readDiscreteData: Too many branches (28/12) Python doesn't have the switch/case statements that C/C++ have. So I could have a large block if/elif/else statements. Is there any way to avoid that? One idiom is to create a dictionary with the values to switch on mapped to callables to handle the case. 6) R:722:waitDiscretes: Too many local variables (38/15) That's new to me. What is wrong with too many local variables? Well, they are just to many. :-) 7) W:933:sendStringToSocket: Redefining name 'nPortNumber' from outer scope (line What is wrong with using the same variable name in a function that is used by its caller? It's not used by the caller but in the outer scope. It may confuse the reader seeing `ham` in the outer scope and then `ham` in the function without noticing that this is actually another `ham`. 8) W:995:sendStringToSocket: Used builtin function 'map' Is that a problem? `map` is deprecated in favor of list comprehensions. A matter of taste… Ciao, Marc 'BlackJack' Rintsch -- http://mail.python.org/mailman/listinfo/python-list
Re: PyLint results?
Em Sex, 2006-04-21 às 13:49 -0400, Michael Yanowitz escreveu:
I ran the new pylint and my code and I had a few questions on why those
are warnings or what I can do to fix them:
You can ignore the warnings you don't like with the --disable-msg
option. Also, you can add a header to the file to apply a rule just to
it.
1) W: 0: Too many lines in module (1587)
Why is 1587 considered too many lines? Would there be necessarily be an
advantage to split it up into 2 or 3 files? Can I up the limit?
Because Python is terse, and this can be a really large module. Or not.
PyLint is not perfect, maybe you should disable this warning.
2) C: 0: Missing required attribute __revision__
What is this? Is that for CVS? I don't use CVS (we use SVN). I have not
seen any sample code which includes this tag yet. But if I include
__revision 1.0 somewhere in the code it will remove that warning?
Don't include the variable just to remove the warning -- disable it.
3) W:230:readDiscreteData: Using the global statement
What is wrong with using the global statement?
Your code can get unmaintainable if you abuse of it. If you really need
it and know how to use it well, disable the warning.
4) W:261:getDiscreteData: Catch Exception
What is wrong with that?
You may catch things you don't want to catch, like KeyboardInterrupt
exceptions.
5) R:547:readDiscreteData: Too many branches (28/12)
Python doesn't have the switch/case statements that C/C++ have. So I
could have a large block if/elif/else statements.
Is there any way to avoid that?
Only splitting the method into 2 or more parts. If that's not possible,
disable the warning.
6) R:722:waitDiscretes: Too many local variables (38/15)
That's new to me. What is wrong with too many local variables?
Can anything be done to improve that besides having too many globals?
The more local variables you have, the more difficult the code is to
read. Or you use less variables, or you split the method into 2 or more
parts, or you disable the warning.
7) W:933:sendStringToSocket: Redefining name 'nPortNumber' from outer scope
(line
What is wrong with using the same variable name in a function that is
used by its caller?
You are hiding something. For example, this code fails strangely (I know
this example isn't that good, but you get the idea):
files = glob('something/*')
for file in files:
# do_something
filename = do_something_with_the_name(file)
# do_something_more
contents = file(filename).read() # fails here
8) W:995:sendStringToSocket: Used builtin function 'map'
Is that a problem?
Sometimes it's slower than list comprehensions, sometimes it's less
legible than list comp. and IIRC GvR doesn't like it, but if you do,
disable the warning.
HTH,
--
Felipe.
--
http://mail.python.org/mailman/listinfo/python-list
