#!/usr/bin/python
from time import clockl = [(x,x) for x in xrange (10000000)]
d = dict(l) t0 = clock() # 方法一
for i in d: n = d[i]t1 = clock() # 方法二：最慢
for k,v in d.items(): n = vt2 = clock() # 方法三: 最快，推荐方法
for k,v in d.iteritems(): n = v t3 = clock() # 方法四
for k,v in zip(d.iterkeys(),d.itervalues()): n = v t4 = clock() print t1 - t0, t2 - t1, t3 - t2, t4 - t3以上代码执行五次，结果分别为：
root@ubuntu:~# python test.py
1.892906 11.893149 1.859164 3.45618
root@ubuntu:~# python test.py
2.038906 11.808548 1.969358 3.498633
root@ubuntu:~# python test.py
2.059066 11.473983 1.96166 3.695533
root@ubuntu:~# python test.py
2.092667 11.372379 1.9519 3.656708
root@ubuntu:~# python test.py
2.082951 12.910404 2.021785 3.663504可见，最快的方法是：
for k,v in d.iteritems(): 
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