python - 与查找和替换相乘

Question

正则表达式可以用来算术吗？例如找到文件中的所有数字并将它们乘以标量值。

Answer 1

您可以使用 re.sub() 实现此目的带有回调:

import re

def repl(matchobj):
  i = int(matchobj.group(0))
  return str(i * 2)

print re.sub(r'\d+', repl, '1 a20 300c')

输出:

2 a40 600c

来自文档:

re.sub(pattern, repl, string[, count])

If repl is a function, it is called for every non-overlapping occurrence of pattern. The function takes a single match object argument, and returns the replacement string.