Regex Split with Delimiters while keeping delimiters

Question

I am trying to split a string with delimiters into an array while keeping the delimiters as well.

The string that I have is: "2+37/4+26".

I want the array to be: [2,+,37,/,4,+,26]

Does this answer your question? [How to split a string, but also keep the delimiters?](/q/2206378/90527) — outis, Aug 17 '22 at 20:37

anubhava · Accepted Answer · 2015-03-26T17:54:17.140

3

You can split using lookarounds:

String[] tok = input.split("(?<=[+*/-])|(?=[+*/-])");

RegEx Demo

Explanation:

(?<=[+*/-])  # when preceding character is one of 4 arithmetic operators
|            # regex alternation
(?=[+*/-])   # when following character is one of 4 arithmetic operators

edited Mar 26 '15 at 17:54

answered Mar 26 '15 at 17:44

anubhava

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I wish you could explain so I could learn from your **great** answer – Kick Buttowski Mar 26 '15 at 17:52
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I've added an explanation in answer, also check the demo link and detailed regex description on regex101 also. – anubhava Mar 26 '15 at 17:54
How would you do it if the string also had parenthesis? I tried to escape the parenthesis/brackets but I got an error. – th3r1singking Mar 26 '15 at 17:54
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**parenthesis** was never part of your question so I don't even know the requirements but probably you can use: `String[] tok = input.split("(?<=[()+*/-])|(?=[()+*/-])");` – anubhava Mar 26 '15 at 17:56
<= means preceding and = means follwing ya? – Kick Buttowski Mar 26 '15 at 18:00
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Yes `(?<=...)` is positive lookbehind and `(?=...)` is positive lookahead – anubhava Mar 26 '15 at 18:02

Regex Split with Delimiters while keeping delimiters

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