为文件中的字符串添加前缀

问题描述

好吧，我在 .txt 文件中有一种电话目录，我想要做的是找到具有这种模式的所有数字，例如829-2234 并将数字 5 附加到数字的开头.

Well i have a sort of telephone directory in a .txt file,what i want to do is find all the numbers with this pattern e.g. 829-2234 and append the number 5 to the beginning of the numbers.

所以结果现在变成了 5829-2234.

so the result now becomes 5829-2234.

我的代码是这样开始的:

my code begins like this:

import os
import re
count=0

#setup our regex
regex=re.compile("\d{3}-\d{4}\s"}

#open file for scanning
f= open("samplex.txt")

#begin find numbers matching pattern
for line in f:
    pattern=regex.findall(line)
    #isolate results
    for word in pattern:
        print word
        count=count+1 #calculate number of occurences of 7-digit numbers
# replace 7-digit numbers with 8-digit numbers
        word= '%dword' %5

好吧，我真的不知道如何附加前缀 5，然后用 5 前缀的 7 位数字覆盖 7 位数字.我尝试了几件事，但都失败了:/

well i don't really know how to append the prefix 5 and then overwrite the 7-digit number with 7-digit number with 5 prefix. I tried a few things but all failed :/

任何提示/帮助将不胜感激:)

Any tip/help would be greatly appreciated :)

谢谢

推荐答案

您快完成了，但是您的字符串格式设置错误.如您所知 5 将始终在字符串中(因为您正在添加它)，您可以:

You're almost there, but you got your string formatting the wrong way. As you know that 5 will always be in the string (because you're adding it), you do:

word = '5%s' % word

请注意，您也可以在此处使用字符串连接:

Note that you can also use string concatenation here:

word = '5' + word

甚至使用str.format():

word = '5{}'.format(word)

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