regex capturing with repeating pattern

Question

I'm trying to capture all parts of a string, but I can't seem to get it right.

The string has this structure: 1+22+33. Numbers with an operator in between. There could be any number of terms.

What I want is ["1+22+33", "1", "+", "22", "+", "33"]

But I get: ["1+22+33", "22", "+", "33"]

I've tried all kinds of regexes, this is the best I've got, but it's obviously wrong.

let re = /(?:(\d+)([+]+))+(\d+)/g;
let s = '1+22+33';
let m;
while (m = re.exec(s))
  console.log(m);

Note: the operators may vary. So in reality I'd look for [+/*-].

score 2 · Accepted Answer · answered Apr 08 '18 at 13:15

2

You can simply use String#split, like this:

const input = '3+8 - 12'; // I've willingly added some random spaces

console.log(input.split(/\s*(\+|-)\s*/)); // Add as many other operators as needed

answered Apr 08 '18 at 13:15

Jeto

13,447
2
22
39

score 1 · Answer 2 · edited Apr 08 '18 at 13:10

1

Just thought of a solution: /(\d+)|([+*/-]+)/g;

edited Apr 08 '18 at 13:10

revo

43,830
14
67
109

answered Apr 08 '18 at 13:03

fwend

1,781
2
14
15

This regex won't work as it has an unescaped delimiter in it. It will also match 1-+*/23 which I presume isn't really legal? – Nick Apr 08 '18 at 13:10
Right that multiplier is wrong. I've noticed that it depends on the regex engine whether or not you need to escape these operators in a class. I'm using this on node.js, and it works fine, but I guess it makes my code less portable. – fwend Apr 08 '18 at 13:27

score 1 · Answer 3 · answered Apr 08 '18 at 13:19

1

You only have to split on digits:

console.log(
  "1+22+33".split(/(\d+)/).filter(Boolean)
);

answered Apr 08 '18 at 13:19

revo

43,830
14
67
109

regex capturing with repeating pattern

3 Answers3

Linked