python - How to find the max object 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:

currmax = 0
def mymax(s):
  for i in s :
    #assume arity() attribute is present
    currmax = i.arity() if i.arity() > currmax else currmax

Is there a clean pythonic way of doing this?

Answer 1

max(s, key=operator.methodcaller('arity'))

or

max(s, key=lambda x: x.arity())