如何拆分字符串，还要保留分隔符？ [英] How to split a string, but also keep the delimiters?

问题描述

我有一个多行字符串，由一组不同的分隔符分隔：

I have a multiline string which is delimited by a set of different delimiters:

(Text1)(DelimiterA)(Text2)(DelimiterC)(Text3)(DelimiterB)(Text4)

我可以将此字符串拆分为其部分，使用 String.split ，但似乎我无法获得与分隔符正则表达式匹配的实际字符串。

I can split this string into its parts, using String.split, but it seems that I can't get the actual string, which matched the delimiter regex.

换句话说，这就是我得到的：

In other words, this is what I get:

• Text1


• Text2


• Text3


• Text4

• Text1
• Text2
• Text3
• Text4

这是什么我想要

• Text1


• DelimiterA


• Text2


• DelimiterC


• Text3


• DelimiterB


• Text4

• Text1
• DelimiterA
• Text2
• DelimiterC
• Text3
• DelimiterB
• Text4

是否有任何JDK方法可以使用分隔符正则表达式来拆分字符串，但也保留了分隔符rs？

Is there any JDK way to split the string using a delimiter regex but also keep the delimiters?

推荐答案

您可以使用Lookahead和Lookbehind。像这样：

You can use Lookahead and Lookbehind. Like this:

System.out.println(Arrays.toString("a;b;c;d".split("(?<=;)")));
System.out.println(Arrays.toString("a;b;c;d".split("(?=;)")));
System.out.println(Arrays.toString("a;b;c;d".split("((?<=;)|(?=;))")));

您将得到：

[a;, b;, c;, d]
[a, ;b, ;c, ;d]
[a, ;, b, ;, c, ;, d]

最后一个是你想要的。

（（？< =;）|（？=;））等于在; 之前或<$ c之后选择一个空字符$ c>; 。

希望这会有所帮助。

编辑 Fabian Steeg对可读性的评论是有效的。可读性始终是RegEx的问题。有一件事，我做的是帮助缓解这个问题是创建一个变量，其名称代表正则表达式的作用，并使用Java String格式来帮助实现。像这样：

EDIT Fabian Steeg comments on Readability is valid. Readability is always the problem for RegEx. One thing, I do to help easing this is to create a variable whose name represent what the regex does and use Java String format to help that. Like this:

static public final String WITH_DELIMITER = "((?<=%1$s)|(?=%1$s))";
...
public void someMethod() {
...
final String[] aEach = "a;b;c;d".split(String.format(WITH_DELIMITER, ";"));
...
}
...

这有助于一点点。 :-D

This helps a little bit. :-D

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