if any('a','b','c') in ['b','x','y','z']:
    #now i want to assign the matched 'b' to a variable concisely.
    #In case of multiple matches , any match/ first match may be assigned

lst = ['b','x','y','z']
if 'a' in lst:
    var = 'a'
elif 'b' in lst"
    var = 'b'
# and so on