dict字典循环遍历,从测试结果看,iteritems比items快一个数量级
In [32]: def add_dic(a, num):
...: for i in range(num):
...: a[i] = "value" + str(i)
...:
In [33]: def xun(a):
...: print "begin"
...: for key, value in a.items():
...: continue
...: print "over"
...:
In [34]: def xun1(a):
...: print "begin"
...: for key, value in a.iteritems():
...: continue
...: print "over"
...:
In [35]: add_dic(a, 1000000)
In [36]: time xun(a)
begin
over
CPU times: user 728 ms, sys: 0 ns, total: 728 ms
Wall time: 733 ms
In [37]: time xun1(a)
begin
over
CPU times: user 56 ms, sys: 0 ns, total: 56 ms
Wall time: 57.9 ms