如何从txt文件中删除特定行和以下n行? [英] How to delete a specific line and the following n lines from a txt file?

问题描述

我正在创建一个程序来更新文本文件，该文件具有城市列表:

I'm creating a program to update a text file, that has a list of cities:

New York City
New York
USA

Newark
New Jersey
USA

Toronto
Ontario
Canada

如果我想使用bash脚本删除Newark的详细信息，可以执行以下操作:

If I wanted to delete the details for Newark using a bash script, I can do this:

sed -i "/Newark/,+3d" test.txt

这会让我留下以下内容:

And that would leave me with the following:

New York City
New York
USA

Toronto
Ontario
Canada

但是，我想在Python中执行此操作，在Newark之后，我在解决如何删除以下行时遇到了问题.我可以删除纽瓦克:

However, I would like to do this in Python, and I'm having issues figuring out how to delete the following lines, after the line with Newark. I can delete Newark:

with open('test.txt') as oldfile, open('test2.txt', 'w') as newfile:
        for line in oldfile:
            if not "Newark" in line:
                newfile.write(line)

os.remove('test.txt')
os.rename('test2.txt', 'test.txt')

但这对其余两行无效，并创建了一个新文件，我不得不用它来替换原始文件.

But this does nothing for the remaining two lines, and creates a new file I then have to use to replace the original file.

1. 如何使用Python模仿sed命令的功能?
2. 有什么方法可以进行文件内编辑，因此我不必每次都需要从文件中删除文件时创建并替换文件吗?

推荐答案

带有计数器?在这里:

with open('test.txt') as oldfile, open('test2.txt', 'w') as newfile:
    skip = 0
    for line in oldfile:
        if "Newark" in line:
            skip = 3
        elif skip > 0:
            skip = skip - 1
        else:
            newfile.write(line)

我只回答了第一个问题.文件输入支持文件编辑，请在此处查看:就地，因为

I only answered the first question. fileinput support file editing, please have a look here: How to search and replace text in a file? Btw, I would recommend also in-place because it doesn't hijack stdout

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