cmp_example.py

# -*- coding: utf-8 -*-
"""
Created on Wed Jan 02 11:03:42 2013

@author: qzhang
"""
import functools
a = [ 1,50,2,4,16]

def MyCmp(x,y):
    return cmp(y,x)     

print sorted(a,cmp=cmp)
print sorted(a,cmp = MyCmp)

#make a key function using cmp_to_key()
get_key = functools.cmp_to_key(MyCmp)

for i in a:
    print get_key(i).obj

#sort it by key, but not by cmp
print sorted(a,key=get_key)