def slowest_replace():
replace_list = []
for i, char in enumerate(orignal_str):
c = char if char != " " else "-"
replace_list.append(c)
return "".join(replace_list)
def slow_replace():
replace_str = ""
for i, char in enumerate(orignal_str):
c = char if char != " " else "-"
replace_str += c
return replace_str
$ python -m timeit -n 1000000 '"I like to reading.".replace(" ", "-")'
1000000 loops, best of 3: 0.253 usec per loop
$ python -m timeit -s 'orignal_str = "I like to reading."' '"-".join(orignal_str.split())'
1000000 loops, best of 3: 0.53 usec per loop
具体参数使用可以用命令 python -m timeit -h 查看帮助。使用较多的是下面的选项:
-s S, –setup=S: 用来初始化statement中的变量,只运行一次;
-n N, –number=N: 执行statement的次数,默认会选择一个合适的数字;
-r N, –repeat=N: 重复测试的次数,默认为3;