finding max in python as per some custom criterion

Question

I can do max(s) to find the max of a sequence. But suppose I want to compute max according to my own function , something like so -

currmax = 0
def mymax(s)          


        

Answer 1

I think the generator expression of doublep is better, but we seldom get to use methodcaller, so...

from operator import methodcaller
max(map(methodcaller('arity'), s))