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

Use concatenation:

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

In other words, generate a sublist that either has the optional element in it, or is 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 for more elements too, of course:

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

You can do it with a slice

x = [1, 3, 4][not conditional:]

>>> conditional = False
>>> [1, 3, 4][not conditional:]
[3, 4]
>>> conditional = True
>>> [1, 3, 4][not conditional:]
[1, 3, 4]

Related