python - Sort with two key value -

i'm trying convert code, , ran line, , i'm not sure does. know can sort using key a:a*a, how handle 2 keys?

this line trying convert (to c#, if matters):

 arr.sort(lambda a,b:a-b) 

https://docs.python.org/2/tutorial/datastructures.html

list.sort(cmp=none, key=none, reverse=false)

sort items of list in place (the arguments can used sort customization, see sorted() explanation).

https://docs.python.org/2/library/functions.html#sorted

cmp specifies custom comparison function of 2 arguments (iterable elements) should return negative, 0 or positive number depending on whether first argument considered smaller than, equal to, or larger second argument: cmp=lambda x,y: cmp(x.lower(), y.lower()). default value none.

lambda a,b defining anonymous function in python.

so same

def f(a,b):     return a-b  arr.sort(f) 

which naturally returns > 0 if a > b , 0 if a==b.

as @martijnpieters points out, should plain "natural" sorting and, in absence of operator overloading (e.g. plain integers), same sort() no arguments.