Does Python have a cleaner way to express "if x contains a|b|c|d..."?
PythonIf StatementPython 3.xSubstringPython Problem Overview
The Pythonic way to check if a string x is a substring of y is:
if x in y:
Finding if x is equivalent to a, b, c, d, e, f or g is also Pythonic:
if x in [a,b,c,d,e,f,g]:
But checking if some string x contains either a, b, c, d, e, f or g seems clunky:
if a in x or b in x or c in x or d in x or e in x or f in x or g in x
Is there a more Pythonic method of checking if a string x contains an element of a list?
I know it is trivial to write this myself using a loop or using a regex:
re.search('(dog|cat|bird|mouse|elephant|pig|cow)', x)
but I was wondering if there was a cleaner way that does not involve regex.
Python Solutions
Solution 1 - Python
The Pythonic approach would be to use any():
if any(s in x for s in (a,b,c,d,e,f,g)):
From the linked documentation:
>any(iterable)
>Return True if any element of the iterable is true. If the iterable is empty, return False. Equivalent to: > def any(iterable): for element in iterable: if element: return True return False
Also, notice that I've used a tuple instead of a list here. If your a-g values are pre-defined, then a tuple would indeed be preferred. See: Are tuples more efficient than lists in Python?
Solution 2 - Python
if any(q in x for q in [a,b,c,d,e,f,g]):
I think that's about as short & Pythonic as you can get it.
Solution 3 - Python
A bit late to the party, but
not frozenset(x).isdisjoint(frozenset(y))
would work, and may be faster (algorithmically, but maybe not for smaller test cases).
Solution 4 - Python
without using any but simply max
def is_in(symbol, lst):
return max([symbol in x for x in lst])
print is_in('a',['ae','br','tl'])
print is_in('c',['ae','br','tl'])
gives
>>>
True
False