Pylint, PyChecker or PyFlakes? [closed]

Question

I would like to get some feedback on these tools on:

• features;
• adaptability;
• ease of use and learning curve.

Answer 1

Well, I am a bit curious, so I just tested the three myself right after asking the question ;-)

Ok, this is not a very serious review, but here is what I can say:

I tried the tools with the default settings (it's important because you can pretty much choose your check rules) on the following script:

#!/usr/local/bin/python # by Daniel Rosengren modified by e-satis  import sys, time stdout = sys.stdout  BAILOUT = 16 MAX_ITERATIONS = 1000  class Iterator(object) :      def __init__(self):          print 'Rendering...'         for y in xrange(-39, 39):             stdout.write('\n')             for x in xrange(-39, 39):                 if self.mandelbrot(x/40.0, y/40.0) :                     stdout.write(' ')                 else:                     stdout.write('*')       def mandelbrot(self, x, y):         cr = y - 0.5         ci = x         zi = 0.0         zr = 0.0          for i in xrange(MAX_ITERATIONS) :             temp = zr * zi             zr2 = zr * zr             zi2 = zi * zi             zr = zr2 - zi2 + cr             zi = temp + temp + ci              if zi2 + zr2 > BAILOUT:                 return i          return 0  t = time.time() Iterator() print '\nPython Elapsed %.02f' % (time.time() - t) 

As a result:

• PyChecker is troublesome because it compiles the module to analyze it. If you don't want your code to run (e.g, it performs a SQL query), that's bad.
• PyFlakes is supposed to be light. Indeed, it decided that the code was perfect. I am looking for something quite severe so I don't think I'll go for it.
• PyLint has been very talkative and rated the code 3/10 (OMG, I'm a dirty coder !).

Strong points of PyLint:

• Very descriptive and accurate report.
• Detect some code smells. Here it told me to drop my class to write something with functions because the OO approach was useless in this specific case. Something I knew, but never expected a computer to tell me :-p
• The fully corrected code run faster (no class, no reference binding...).
• Made by a French team. OK, it's not a plus for everybody, but I like it ;-)

Cons of Pylint:

• Some rules are really strict. I know that you can change it and that the default is to match PEP8, but is it such a crime to write 'for x in seq'? Apparently yes because you can't write a variable name with less than 3 letters. I will change that.
• Very very talkative. Be ready to use your eyes.

Corrected script (with lazy doc strings and variable names):

#!/usr/local/bin/python # by Daniel Rosengren, modified by e-satis """ Module doctring """   import time from sys import stdout  BAILOUT = 16 MAX_ITERATIONS = 1000  def mandelbrot(dim_1, dim_2):     """     function doc string     """     cr1 = dim_1 - 0.5     ci1 = dim_2     zi1 = 0.0     zr1 = 0.0      for i in xrange(MAX_ITERATIONS) :         temp = zr1 * zi1         zr2 = zr1 * zr1         zi2 = zi1 * zi1         zr1 = zr2 - zi2 + cr1         zi1 = temp + temp + ci1          if zi2 + zr2 > BAILOUT:             return i      return 0  def execute() :     """     func doc string     """     print 'Rendering...'     for dim_1 in xrange(-39, 39):         stdout.write('\n')         for dim_2 in xrange(-39, 39):             if mandelbrot(dim_1/40.0, dim_2/40.0) :                 stdout.write(' ')             else:                 stdout.write('*')   START_TIME = time.time() execute() print '\nPython Elapsed %.02f' % (time.time() - START_TIME) 

Thanks to Rudiger Wolf, I discovered pep8 that does exactly what its name suggests: matching PEP8. It has found several syntax no-nos that Pylint did not. But Pylint found stuff that was not specifically linked to PEP8 but interesting. Both tools are interesting and complementary.

Eventually I will use both since there are really easy to install (via packages or setuptools) and the output text is so easy to chain.

To give you a little idea of their output:

pep8:

./python_mandelbrot.py:4:11: E401 multiple imports on one line ./python_mandelbrot.py:10:1: E302 expected 2 blank lines, found 1 ./python_mandelbrot.py:10:23: E203 whitespace before ':' ./python_mandelbrot.py:15:80: E501 line too long (108 characters) ./python_mandelbrot.py:23:1: W291 trailing whitespace ./python_mandelbrot.py:41:5: E301 expected 1 blank line, found 3 

Pylint:

************* Module python_mandelbrot C: 15: Line too long (108/80) C: 61: Line too long (85/80) C:  1: Missing docstring C:  5: Invalid name "stdout" (should match (([A-Z_][A-Z0-9_]*)|(__.*__))$) C: 10:Iterator: Missing docstring C: 15:Iterator.__init__: Invalid name "y" (should match [a-z_][a-z0-9_]{2,30}$) C: 17:Iterator.__init__: Invalid name "x" (should match [a-z_][a-z0-9_]{2,30}$)  [...] and a very long report with useful stats like :  Duplication -----------  +-------------------------+------+---------+-----------+ |                         |now   |previous |difference | +=========================+======+=========+===========+ |nb duplicated lines      |0     |0        |=          | +-------------------------+------+---------+-----------+ |percent duplicated lines |0.000 |0.000    |=          | +-------------------------+------+---------+-----------+ 

Answer 2

pep8 was recently added to PyPi.

• pep8 - Python style guide checker
• pep8 is a tool to check your Python code against some of the style conventions in PEP 8.

It is now super easy to check your code against pep8.

See http://pypi.python.org/pypi/pep8