Question

How would you make the give code more Pythonic?

I want to get Paths out of the sample like /usr/local/sources/devel/algebra.py: def _alg(...) without the character :.

My code

import os
FunctionPath = "/usr/local/sources/devel/sage-main/build/sage/"
cmd = "grep -R 'def ' %s | cut -d' ' -f1" % (FunctionPath)
cmd += ' &'
raw_path = os.system(cmd)
path = raw_path.replace(':', '')       // not working

print path   

[edit]: The code cannot be written pythonically only with Built-in functions.

Answer 1

Why not do this:

for line in open(FunctionPath):
    line = line.strip()
    if line.startswith('def '):
        print '%s: %s' % (FunctionPath, line.partition(':')[0])

And if you use fileinput module you can iterate over lines from multiple input streams very easily:

import fileinput
for line in fileinput.input(paths):
    line = line.strip()
    if line.startswith('def '):
        print '%s: %s' % (fileinput.filename(), line.partition(':')[0])

BTW, if you don’t give fileinput.input any path it will use sys.argv by default, so you can run your python script like this:

$ python script.py filepath1 filepath2 filepath3

fileinput will read the files for you.

if you really want to cover all cases, you shouldn’t be using replace(‘:’, ”) because it is possible to have

def func(): #comment myfunc():
   pass

The following will give you the correct result:

>>> 'def func(): #comment myfunc():'.partition(':')[0]
'def func()'

Unless you want the comment as well.