Regex do not match content but whole searched string

Question

I'm using this regex to match an "href" attribute in a <a> tag:

var href_matches = postRep.match(/href="(.*?)"/g);

The regex matches correctly the href except it returns the whole "href=http:example.com" string.
How do I manage to get only the href value (eg. "example.com")?

Possible duplicate of [JavaScript regular expressions and sub-matches](http://stackoverflow.com/questions/844001/javascript-regular-expressions-and-sub-matches) — Flint, Sep 04 '16 at 19:16

score 1 · Accepted Answer · answered Sep 04 '16 at 19:14

1

You can either run exec() on the regex :

var url_match = /href="(.*?)"/g.exec(postRep);

or remove the global flag

var url_match = postRep.match(/href="(.*?)"/);

Using String's match() function won't return captured groups if the global modifier is set.

answered Sep 04 '16 at 19:14

Flint

1,651
1
19
29

I went with the "exec" solution above and looped each result. Really thanks for that, Flint! It worked – Salvatore Tempesta Sep 07 '16 at 17:21

Georgi Naumov · Answer 2 · 2016-09-04T20:33:57.960

1

Just another idea.

You can try something like this function:

function getHrefs(inputString) {
    var out = [];
    inputString.replace(/\bhref\b=['"]([^'"]+)['"]/gi, function(result, backreference) {
        out.push(backreference);
        return '';
    });
    return out;
}

Improved solution (much shortest):

function getHrefs(inputString) {
    return (inputString.match(/\bhref\b=['"][^'"]+(?=['"])/gi) || []).map(s => s.replace(/^href=["']/,""));
}

Edit:

There is other option - exec. But with exec you will need loop to get all matches (if you need this).

edited Sep 04 '16 at 20:33

answered Sep 04 '16 at 19:33

Georgi Naumov

4,160
4
40
62

Thanks for this one! But I think the "exec" solution is more straightforward for my needs – Salvatore Tempesta Sep 07 '16 at 17:19

score 0 · Answer 3 · 2016-09-04T19:20:51.370

0

You can use regex lookbehinds to check if the "href=" is there without actually including it in the match. For example, the regex (?<=href=)example\.com applied to href=example.com should only match example.com.

EDIT: This method only works in languages that support regex lookbehinds. Javascript doesn't support this feature. (thanks to Georgi Naumov for pointing this out)

edited Sep 04 '16 at 19:20

answered Sep 04 '16 at 19:10

1

JavaScript regex engine don't support lookbehind. – Georgi Naumov Sep 04 '16 at 19:19
Maybe it would be possible to just use javascript to trim off the "href=" after it gets matched? – Sep 04 '16 at 19:20
Yes. My second solution is similar. There is lookahead but unfortunately we don't have lookbehind. – Georgi Naumov Sep 04 '16 at 20:08

Regex do not match content but whole searched string

3 Answers3