Question

Trying to get my head around some regex using JS .replace to replace an integer with a string.

For example, the string could be:

var string = 'image[testing][hello][0][welcome]';

I want to replace the ‘0’ with another value. I was originally using this:

string.replace( /\[\d\]/g, '[newvalue]');

But when we start replacing double digits or more (12, 200, 3204, you get what I mean), it stops working properly. Not sure how to get it functioning the way I want it too.

Thanks in advance. Greatly appreciated.

Answer 1

You need to specify multiple digits:

string.replace( /\[\d+\]/g, '[newvalue]');

JS Fiddle demo

(Note the demo uses jQuery to iterate through the nodes, but it’s merely a convenience, and has no bearing on the regular expression, it just demonstrates its function.)

The reason your original didn’t work, I think, was because \d matches only a single digit, whereas the + operator/character specifies the preceding (in this case digit) character one or more times.

Reference:

• JavaScript Regular Expressions, at the Mozilla Developer Network.