使用 Python 提取字符串中字符前的数字 [英] Extract Number before a Character in a String Using Python

问题描述

我试图在一系列字符串中提取字符M"之前的数字.字符串可能如下所示:

I'm trying to extract the number before character "M" in a series of strings. The strings may look like:

"107S33M15H"
"33M100S"
"12M100H33M"

所以基本上会有一组由不同字符分隔的数字，并且M"可能会出现不止一次.对于此处的示例，我希望我的代码返回:

so basically there would be a sets of numbers separated by different characters, and "M" may show up more than once. For the example here, I would like my code to return:

33
33
12,33 #doesn't matter what deliminator to use here

我能想到的一种方法是用M"分割字符串，并找到纯数字的项目，但我怀疑有更好的方法来做到这一点.非常感谢您的帮助.

One way I could think of is to split the string by "M", and find items that are pure numbers, but I suspect there are better ways to do it. Thanks a lot for the help.

推荐答案

您可以使用简单的 (\d+)M 正则表达式(1+ digit(s) 后跟 M 使用 re.findall 将数字捕获到捕获组中.

You may use a simple (\d+)M regex (1+ digit(s) followed with M where the digits are captured into a capture group) with re.findall.

参见 IDEONE 演示:

import re
s = "107S33M15H\n33M100S\n12M100H33M"
print(re.findall(r"(\d+)M", s))

这是一个正则表达式演示

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