Python遍曆字典的四種方法對比

標籤：python

#!/usr/bin/pythonfrom 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，推薦方法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

以上代碼執行五次，結果分別為：

root@ubuntu:~# python test.py1.892906 11.893149 1.859164 3.45618root@ubuntu:~# python test.py2.038906 11.808548 1.969358 3.498633root@ubuntu:~# python test.py2.059066 11.473983 1.96166 3.695533root@ubuntu:~# python test.py2.092667 11.372379 1.9519 3.656708root@ubuntu:~# python test.py2.082951 12.910404 2.021785 3.663504

可見，最快的方法是：

for k,v in d.iteritems():     ...

Python遍曆字典的四種方法對比