我有一个由一组不同分隔符分隔的多行字符串:
I have a multiline string which is delimited by a set of different delimiters:
(Text1)(DelimiterA)(Text2)(DelimiterC)(Text3)(DelimiterB)(Text4)我可以使用 String.split 将这个字符串拆分成它的部分,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
这就是我想要的
- 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拆分字符串但同时保留分隔符?
Is there any JDK way to split the string using a delimiter regex but also keep the delimiters?
推荐答案可以使用lookahead和lookbehind,它们是正则表达式的特性.
You can use lookahead and lookbehind, which are features of regular expressions.
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("((?<=;)|(?=;))")));你会得到:
[a;, b;, c;, d] [a, ;b, ;c, ;d] [a, ;, b, ;, c, ;, d]最后一个是你想要的.
((?<=;)|(?=;)) 等于在之前选择一个空字符; 或;.
Fabian Steeg 对可读性的评论是有效的.可读性始终是正则表达式的问题.为了使正则表达式更具可读性,我所做的一件事是创建一个变量,其名称表示正则表达式的作用.您甚至可以放置占位符(例如 %1$s)并使用 Java 的 String.format 将占位符替换为您需要使用的实际字符串;例如:
Fabian Steeg's comments on readability is valid. Readability is always a problem with regular expressions. One thing I do to make regular expressions more readable is to create a variable, the name of which represents what the regular expression does. You can even put placeholders (e.g. %1$s) and use Java's String.format to replace the placeholders with the actual string you need to use; for example:
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, ";")); ... }更多推荐
如何拆分字符串,同时保留分隔符?
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