Can I optionally include one element in a list without an else statement in python? -

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i know can in python:

>>> conditional = false >>> x = [1 if conditional else 2, 3, 4] [ 2, 3, 4 ]

but how this?

>>> conditional = false >>> x = [1 if conditional, 3, 4] [ 3, 4 ]

that is, don't want substitute 1 number. want omit if conditional false.

use concatenation:

x = ([1] if conditional else []) + [3, 4]

in other words, generate sublist either has optional element in it, or empty.

demo:

>>> conditional = false >>> ([1] if conditional else []) + [3, 4] [3, 4] >>> conditional = true >>> ([1] if conditional else []) + [3, 4] [1, 3, 4]

this concept works more elements too, of course:

x = ([1, 2, 3] if conditional else []) + [4, 5, 6]

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