Most pythonic way to extend a list to exactly a certain length? [duplicate]

Answer 1

Why not use conditional logic?

def pad_or_slice(L, n):
    if len(L) < n:
        return L + ([0] * (n - len(L)))
    else:
        return L[:n]

This way you're only doing one of the two, not both, at the cost of checking the length of the list, which shouldn't be too costly.