#!/usr/bin/python2

import profile

N = 100000
L = range(0, N) # = [0, 1, 2, 3, ... N-3, N-2, N-1]

# now, four ways to create a new list, such that each element is twice
# the corresponding element in L.  [0, 1, 2, 3, ...] -> [0, 2, 4, 6, ...]

def test_concat_loop():
    L2 = []
    for n in L:
        L2 = L2 + [n*2]

def test_append_loop():
    L2 = []
    for n in L:
        L2.append(n*2)

def test_def_map():
    def tmpfunc(arg):
        return arg * 2
    L2 = map(tmpfunc, L)

def test_lambda_map():
    L2 = map(lambda n: n*2, L)
    
def test_comp():
    L2 = [ n*2 for n in L ]

def test():
    # the concatenation method is an order of magnitude slower than
    # the next best method
    #test_concat_loop()
    test_append_loop()
    test_def_map()
    test_lambda_map()
    test_comp()

# note: this is for an EASY operation, one that does not require a function
# call.  I'm pretty sure the function call is what's killing the map/def and
# map/lambda methods.  If you NEED a function call, then they're not so bad.

profile.run('test()')