how to replace string in javascript using RegExp?

Question

there is a string and RegExp:

var str = "a1c a23c a456c 123";
var re = /a(\d*)c/g;

I want to match all number between a and c, and replace it to b, the result I would like is:

"abc abc abc 123"

how to do it?

Your regex would also match "ac" with no number - is that deliberate? — nnnnnn
– nnnnnn, Commented Feb 22, 2017 at 5:40

RaR · Accepted Answer · 2017-02-22 05:40:25Z

3

Try this

    var str = "a1c a23c a456c 123";
    var re = /(a)(\d*)(c)/g;
    
    console.log(str.replace(re, '$1b$3'));

EDIT:

If ac should not become abc, then regex should be /(a)(\d+)(c)/g

answered Feb 22, 2017 at 5:36

RaR

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3 Comments

This would also replace "ac" with "abc".

If we don't want to, then regex should be /(a)(\d+)(c)/g

No need of capturing group as both characters are static.

Mr_Green · Accepted Answer · 2017-02-22 07:03:35Z

2

Try this:

var str = "a1c a23c a456c 123";
var newStr = str.replace(/\ba\d+c\b/g, "abc");
console.log(newStr);

answered Feb 22, 2017 at 5:40

Mr_Green

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No need of capturing group /\ba\d+c\b/g, 'abc'.