What's the convinient way to evaluate multiple string equality in Python? [duplicate]

Question

I'm really stuck in evaluating Boolean expressions. See the code:

def f(A):
    if A=='a' or A=='b' or A=='c' ...:
        return True
    return False

Is there any convenient and elegant way to do this when A can equal to even more strings?

Answer 1

If you do this check often and/or have a lot of possible values consider using a set. Lookup time for a set is O(1), lookup time for a list is O(n).

if A in {'a', 'b', 'c', ...}:
    # do something