【原】Python字符串操作--寻找所有匹配的位置

You said I was your life. Are you still alive when you lost it?

下面给出两种方法

1. 使用find函数来实现

def find_all(string, sub): start = 0 pos = [] while True: start = string.find(sub, start) if start == -1: return pos pos.append(start) start += len(sub)

print(find_all('You said I was your life. Are you still alive when you lost it?', 'y'))


string里面存了完整的字符串，find函数有两个参数，第一个参数sub，是需要寻找的子字符串，start是从string的什么地方开始寻找sub。找到之后将位置信息保存到pos中。然后start往后移动一个sub的长度，开始寻找第二个匹配的位置，一直到返回-1，证明找不到了，就返回pos，里面保存了所有sub的位置信息。

2.使用re包来实现

import re
string = 'You said I was your life. Are you still alive when you lost it?'pattern = 'you'for m in re.finditer(pattern, string): print(m.start(), m.end())


直接通过循环来实现，然后返回找到的pattern的起始位置和终止位置。