Search code examples
pythonpylint

PyLint W0143 warning: Comparing against a callable


I trying to test pylint with default settings and (see python code below) get a warning:

>pylint pylint_test_01.py
>pylint_test_01.py:24:7: W0143: Comparing against a callable, did you omit the parenthesis? (comparison-with-callable)

How can I get rid of this pylint warning without breaking this algorithm and without disable pylint checks (i.e. with default settings)? General principle of enumerating functions from list should remain.

'''Test pylint with default settings warnings'''
from random import randint
def sortaray_builtin(arr):
    '''This is built in Python sort function'''
    return sorted(arr.copy())
def sortaray_bubble(arr):
    '''Bubble sorting algorithm -- is a simplest of sorting algorithms. Perfomance: O(N**2)'''
    brr = arr.copy()
    for i, _ in enumerate(brr[:-1]):
        for j in range(i, len(brr)):
            if brr[i] > brr[j]:
                brr[i], brr[j] = brr[j], brr[i]
    return brr

SFUNCTIONS = [
    sortaray_builtin,
    sortaray_bubble
]

ARSIZE = 20
ARRY = [randint(0, ARSIZE) for i in range(ARSIZE)]

for SrtFunc in SFUNCTIONS:
    # Line below cause an W0143: Comparing against a callable, did you omit the parenthesis? (comparison-with-callable)
    if SrtFunc == sortaray_builtin:
        print("Builtin: ", end='', flush=True)
    else:
        print("Bubble : ", end='', flush=True)
    print(SrtFunc(ARRY))

Solution

  • Option 1

    You can disable checks for some places.

    if SrtFunc == sortaray_builtin:  # pylint: disable=W0143
    

    More info https://pylint.readthedocs.io/en/latest/user_guide/message-control.html

    Option 2

    You can get the name of a function with __name__ attribute.

    SrtFunc.__name__ == builtin_sort.__name__
    

    Option 3

    Same as the second method, but with .__doc__

    SrtFunc.__doc__ == builtin_sort.__doc__
    

    Option 4

    You can wrap your functions in objects, e.g. in dict, or create a special class.

    class Sorter():
        def __init__(self, func):
            self.sort = func
    builtin = Sorter(sortaray_builtin)
    bubble = Sorter(sortaray_bubble)
    SFUNCTIONS = [ builtin, bubble ]
    builtin.sort()