在Java中的文本文件中切换两行 [英] Switching two lines in a text file in Java

问题描述

我已经坚持了一段时间，我终于决定请求帮助. 因此，我有一个小的文本文件，用户想要从中切换2行，用户输入2行的索引，因此我必须切换em. 到目前为止，我的想法是使用带有2个正则表达式的replaceALL ，但是A:可能不会切换它们，而只是最终将它们替换为另一个，给我留了一个副本，而B:我不知道如何使用正则表达式来定位第n行； 或使用-Files.readAllLines(Paths.get(name)).get(index);得到两条线，但是我仍然在实际切换过程中苦苦挣扎.

I've been stuck on this for a while and I've finally decided to plead for help. So I have a small text file and the user wants to switch 2 lines from it, the user enters the indexes of the 2 lines and I have to switch em. So far my ideas have been to either use replaceALL with 2 regexes , but A: That probably won't switch them but just end up replacing one with the other, leaving me with a duplicate and B: I have no idea how to locate the nth line using regex; or use - Files.readAllLines(Paths.get(name)).get(index); to get the two lines but then I'm still struggling with the actual switching process.

推荐答案

您可以使用

• Files.readAllLines将所有行作为列表获取
• 交换列表的两个元素.例如Collections.swap
• 写回所有行以更新文件.

• Files.readAllLines to get all lines as a list
• swap the two elements of the list. e.g. Collections.swap
• write all the lines back out to update the file.

如果您需要能够处理大文件，则可以

If you need to be able to work with large files you could

• 使用RandomAccessFile通过从文件的开头进行读取来查找所需行的开头/结尾.
• 将这两行读入缓冲区.
• 将两行写到位，但四处交换.

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