Question

Consider this example:

l = [1, 2, 3, 4, 5]

for values in l:
    if values == 1:
        print('yes')
    elif values == 2:
        print('no')
    else:
        print('idle')

Rather than printing the results, I want to use a list comprehension to create a list of results, like ['yes', 'no', 'idle', 'idle', 'idle'].

How can we represent the elif logic in a list comprehension? Up until now, I have only used if and else in list comprehension, as in if/else in a list comprehension.

Answer 1

Python’s conditional expressions were designed exactly for this sort of use-case:

>>> l = [1, 2, 3, 4, 5]
>>> ['yes' if v == 1 else 'no' if v == 2 else 'idle' for v in l]
['yes', 'no', 'idle', 'idle', 'idle']