用文本文件中的n +字符串替换字符串的每n次出现

Question

文本文件包含

This is line ABC XYZ. This is something. This is ABC XYZ. foo. This is ABC XYZ. foo

所需的输出是

This is line 1 ABC XYZ. This is something. This is 2 ABC XYZ. foo. This is 3 ABC XYZ. foo 

所以，问题是由n个 ABC XYZ更换ABC XYZ的第n次出现。

Answer 1

您可以使用列表理解

a="This is line ABC XYZ. This is something. This is ABC XYZ. foo. This is ABC XYZ. foo"
''.join([e+str(c+1)+" ABC XYZ" for c,e in enumerate(a.split("ABC XYZ"))][0:-1])+a.split("ABC XYZ.")[-1]

Answer 2

re.sub方法可以将函数作为第二个参数。 将有状态函数与itertools.count对象一起用作计数器。

码

import re, itertools

s = 'This is line ABC XYZ. This is something. This is ABC XYZ. foo. This is ABC XYZ. foo'

def enumerator():
    counter = itertools.count(1)

    return lambda m: '{} {}'.format(next(counter), m.group())

out = re.sub(r'ABC XYZ', enumerator(), s)

print(out)

函数enumerator器可用于任何模式。

输出量

This is line 1 ABC XYZ. This is something. This is 2 ABC XYZ. foo. This is 3 ABC XYZ. foo

Answer 3

代码 ：

import re

text = "This is line ABC XYZ. This is something. This is ABC XYZ. foo. This is ABC XYZ. foo"
x = re.split("(ABC XYZ)",text)
c=0
for i,s in enumerate(x):
    if re.match('(ABC XYZ)',x[i]):
        c+=1
        x[i] = str(c)+' '+x[i]
x = ''.join(x)   # This is line 1 ABC XYZ. This is something. This is 2 ABC XYZ. foo. This is 3 ABC XYZ. foo

您可以使用更优化的方法来执行此操作，但这将有助于您更好地理解它。