为什么String.split需要竖线分隔符进行转义？ [英] Why does String.split need pipe delimiter to be escaped?

问题描述

我试图解析与管道分隔值每行一个文件。
当我没逃过拆分法管道分隔符它没有正常工作，它的工作后，正确逃出我下面的管道。

I am trying to parse a file that has each line with pipe delimited values. It did not work correctly when i did not escape the pipe delimiter in split method, it worked correctly after i escaped the pipe as below.

private ArrayList<String> parseLine(String line) {
    ArrayList<String> list = new ArrayList<String>();
    String[] list_str = line.split("\\|"); // note the escape "\\" here
    System.out.println(list_str.length);
    System.out.println(line);
    for(String s:list_str) {
        list.add(s);
        System.out.print(s+ "|");
    }
    return list;
}

有人可以解释为什么管道字符需要转义为拆分（）方法？

推荐答案

String.split 预计经常EX pression说法。一个转义 | 被解析为一个正则表达式的意思是空字符串或空字符串，这是不是你的意思

String.split expects a regular expression argument. An unescaped | is parsed as a regex meaning "empty string or empty string," which isn't what you mean.

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