python效率提升专题-循环

import time
oldstr = "football" * 1000000
oldlist = [x for x in oldstr]

def loopA():
newlist = []
t = time.time()
for word in oldlist:
newlist.append(word.upper())

print "method A cost:%.3fs" % (time.time()-t)
del newlist

def loopB():
t = time.time()
newlist = [x.upper() for x in oldlist]
print "method B cost:%.3fs" % (time.time()-t)
del newlist

def loopC():
t = time.time()
newlist = map(str.upper, oldlist)
print "method C cost:%.3fs" % (time.time()-t)
del newlist

loopA()
loopB()
loopC()