# modified by cpbotha@ieee.org <http://cpbotha.net/> from this posting:
# http://mail.python.org/pipermail/python-list/2000-December/022606.html

import time
import operator

def withMapSQR(inList):
    return map(lambda x: x**2.0, inList)

def withMapDBL(inList):
    return map(operator.mul, inList, inList)

def withLCSQR(inList):
    return [x**2.0 for x in inList]

def withLCDBL(inList):
    return [x*x for x in inList]

def withLoopSQR(inList):
    l = len(inList)
    result = [None]*l
    for i in range(l):
        result[i] = inList[i]**2
    return result

def withLoopDBL(inList):
    l = len(inList)
    result = [None]*l
    for i in range(l):
        result[i] = inList[i]*inList[i]
    return result


def stopWatch(function, N=100*1000):
    start = time.clock()
    nlist = map(lambda x: 1.0 * x, range(N))
    function(nlist)
    stend = time.clock()
    return stend-start

print "Using map and lambda (**2):               %f" % stopWatch(withMapSQR)
print "Using map without lambda (list doubling): %f" % stopWatch(withMapDBL)
print "Using list-comprehension (**2):           %f" % stopWatch(withLCSQR)
print "Using list-comprehension (elem doubling): %f" % stopWatch(withLCDBL)
print "Using a simple loop (**2):                %f" % stopWatch(withLoopSQR)
print "Using a simple loop (elem doubling):      %f" % stopWatch(withLoopDBL)