python list 和 tuple, dict 用于迭代代价

#!/usr/bin/env python #-*- coding:utf-8 -*- import time start = time.time() for i in range(1000000): a = (1, 2, 3, 4) print time.time() - start start = time.time() for i in range(1000000): a = [1, 2, 3, 4] print time.time() - start

如果要迭代一列数据，用tuple比list优。

0.107225894928 0.200721979141

结果可以看出，生成1000000数据产生的结果不一样。

 

test = dict((i, i) for i in range(1, 1001)) start = time.time() for i in range(1000000): if i in test: pass print time.time() - start start = time.time() for i in range(1000000): if test.has_key(i): pass print time.time() - start

另外，判断key是否存在时，用in 比 has_key优 

0.151313066483 0.189944982529

 

转载于:https://www.cnblogs.com/zhuangzebo/p/3534088.html