Python regex：计算匹配的数字并用结果替换

Question

我想匹配以下内容：

- [Michael - YouTube](https://www.youtube.com/watch?v=3nsoN-LS8RQ){1:00,1:03}

并将其转换为

- [Michael - YouTube; **Start:1m 0s; End:1m 3s**](https://www.youtube.com/watch?v=3nsoN-LS8RQ&t=60s) 

<center><iframe width="400" height="300" src="https://www.youtube.com/embed/3nsoN-LS8RQ?start=60&end=63" frameborder="0" allow="accelerometer; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe></center>

我试过了：

# Data.md

    - [Michael - YouTube](https://www.youtube.com/watch?v=3nsoN-LS8RQ){1:00,1:03}

# python3 Test.py < Data.md

import sys
import re
Output = sys.stdin.read()
Pattern = "(.*)\[([^]]*YouTube)\]\(https://www.youtube.com/watch\?.*v=([^&]*)[^)]*\)\{[ ]?*([0-9]?*)[^,]?*:[ ]?*([0-9]?*)[^,]?*[,]?[ ]?*([0-9]?*)[^,]?*:[ ]?*([0-9]?*)[^,]?*\}"
tStart=int(\\4) * 60 + int(\\5)
tEnd=int(\\6) * 60 + int(\\7)
Replace = '\\1[\\2 **Start:\\4m \\5s End:\\6m \\7s**](https://www.youtube.com/watch\?v=\\3&t=',tStart,'s\) <center><iframe width="400" height="300" src="https://www.youtube.com/embed/\\3?start=',tStart,'\&end=',tEnd,' "frameborder="0" allow="accelerometer; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe></center>\n\n'
Output = re.sub(Pattern, Replace, Output)
print('Output')

我如何计算tStart=int(\\4) * 60 + int(\\5) 和tEnd=int(\\6) * 60 + int(\\7)

Answer 1

有点固定的正则表达式看起来像

(.*)\[([^]]*YouTube)]\(https://www\.youtube\.com/watch\?\S*v=([^&]*)[^)]*\)\{[ ]*([0-9]*)[^,]*:[ ]*([0-9]*)[^,]*[,]?[ ]?([0-9]?)[^,]?:[ ]*([0-9]*)[^,]*}

查看regex demo 以查看匹配结构。由于您没有提供正则表达式规范，因此足以解决当前问题：在字符串替换模式中无法使用组内容进行计算。您需要使用回调方法作为替换参数：

import re

Output = "- [Michael - YouTube](https://www.youtube.com/watch?v=3nsoN-LS8RQ){1:00,1:03}"

Pattern = "(.*)\[([^]]*YouTube)]\(https://www\.youtube\.com/watch\?\S*v=([^&]*)[^)]*\)\{[ ]*([0-9]*)[^,]*:[ ]*([0-9]*)[^,]*[,]?[ ]?([0-9]?)[^,]?:[ ]*([0-9]*)[^,]*}"

def ReplaceMatch(m):
    tStart = int(float((m.group(4))))*60 + int(float(m.group(5)))
    tEnd = int(float(m.group(6)))*60 + int(float(m.group(7)))
    return '{0}[{1}; **Start:{3}m {4}s End:{5}m {6}s**](https://www.youtube.com/watch?v={2}&t={7}s)\n\n <center><iframe width="400" height="300" src="https://www.youtube.com/embed/{2}?start={7}&end={8}" frameborder="0" allow="accelerometer; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe></center>\n\n'.format(m.group(1), m.group(2), m.group(3), m.group(4), m.group(5), m.group(6), m.group(7),tStart,tEnd)

Output = re.sub(Pattern, ReplaceMatch, Output)
print(Output)

请参阅Python demo。

输出：

- [Michael - YouTube; **Start:1m 00s End:1m 03s**](https://www.youtube.com/watch?v=3nsoN-LS8RQ&t=60s)

 <center><iframe width="400" height="300" src="https://www.youtube.com/embed/3nsoN-LS8RQ?start=60&end=63" frameborder="0" allow="accelerometer; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe></center>