CS61A SU20 one-liner challenge for disc02, Q1.6

make_keeper.py

import doctest

def make_keeper(n):
    """Returns a function which takes one parameter cond and prints out
    all integers 1..i..n where calling cond(i) returns True.

    >>> def is_even(x):
    ...     # Even numbers have remainder 0 when divided by 2.
    ...     return x % 2 == 0

    >>> make_keeper(5)(is_even)
    2
    4
    """
    return lambda cond: list(map(print, filter(cond, range(1, n + 1)))) and None

doctest.testmod()