First common element from two lists

Question

x = [8,2,3,4,5]
y = [6,3,7,2,1]

How to find out the first common element in two lists (in this case, \"2\") in a concise and elegant way? Any list

Answer 1

This one uses sets. It returns the first common element or None if no common element.

def findcommon(x,y):
    common = None
    for i in range(0,max(len(x),len(y))):
        common = set(x[0:i]).intersection(set(y[0:i]))
        if common: break
    return list(common)[0] if common else None