Python re.split() 与 split() [英] Python re.split() vs split()

问题描述

在我的优化任务中，我发现内置的 split() 方法比等效的 re.split() 方法快 40%.

In my quests of optimization, I discovered that that built-in split() method is about 40% faster that the re.split() equivalent.

一个虚拟基准(易于复制粘贴):

A dummy benchmark (easily copy-pasteable):

import re, time, random 

def random_string(_len):
    letters = "ABC"
    return "".join([letters[random.randint(0,len(letters)-1)] for i in range(_len) ])

r = random_string(2000000)
pattern = re.compile(r"A")

start = time.time()
pattern.split(r)
print "with re.split : ", time.time() - start

start = time.time()
r.split("A")
print "with built-in split : ", time.time() - start

为什么会有这种差异?

推荐答案

re.split 预计会更慢，因为使用正则表达式会产生一些开销.

re.split is expected to be slower, as the usage of regular expressions incurs some overhead.

当然，如果您在常量字符串上进行拆分，则使用 re.split() 毫无意义.

Of course if you are splitting on a constant string, there is no point in using re.split().

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