Javascript regex match doesn't run correctly

Question

okay I give up. Here's my code:

var re = /href="(http.*\.jpg)"/g;
var mp3s = body.match(re);

it finds pictures, but it returns href="http://www.picture.com/smthg.jpg"

instead of returning http://www.picture.com/smthg.jpg

any idea why?

When you have access to the DOM, why bother using something so primitive as regular expressions? It seems pretty naive. — zzzzBov
– zzzzBov, Commented Apr 23, 2014 at 23:23
because it is faster than importing a dom parser library. This really doesn't answer my question. The regex seems fine to me I don't see where is the problem... I capture the group excluding the href — David 天宇 Wong
– David 天宇 Wong, Commented Apr 23, 2014 at 23:25
If you want to make sure that there is a "href=" before your link but not catch it, look up "lookbehind regular expression" in Google, it will do just that. — Louis Ameline
– Louis Ameline, Commented Apr 23, 2014 at 23:29

Felipe · Accepted Answer · 2014-04-23 23:42:36Z

2

The result from match() is actually an object.

I think you need to access the first element on that object.

For example:

body.match(re)[1]

This is where the actual result is kept.

Shameless self-promotion: I've written a small guide for me, I can never remember how to use these either. It's here: http://queirozf.com/reminders/javascript-regular-expressions-usage-reminder

edited Apr 23, 2014 at 23:42

answered Apr 23, 2014 at 23:33

Felipe

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4 Comments

Zlatko Over a year ago

It's not really a self-promotion if you didn't promote yourself - where's your guide at? Can we see it? :)

Felipe Over a year ago

@Zlatko =) ok then there you go.

David 天宇 Wong Over a year ago

I console.log it and I only get one result, the one with the entire thing and not just the capture group.

Zlatko Over a year ago

Now it's a self-promotion :) Though not a shameless one, I think these short reminders are excellent and they can also help out others like this.

Abhas Tandon · Accepted Answer · 2014-04-23 23:23:32Z

0

try

var re = /(http.*\.jpg)/g;
var mp3s = body.match(re);

since you don't need the href.

answered Apr 23, 2014 at 23:23

Abhas Tandon

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1 Comment

David 天宇 Wong Over a year ago

yeah but I want to be sure that it is in a link, not like that.

Andrew Shepherd · Accepted Answer · 2014-04-23 23:44:22Z

0

You want to match the regular expression, but then return just the portion in brackets.

To do this, call the regular expressions exec method. For example:

var body = 'stuff stuff morestuff href="http://www.picture.com/smthg.jpg" and some more stuff';
var re = /href="(http.*\.jpg)"/g;
var regexResults = re.exec(body);
var mp3s = regexResults[1];
alert(mp3s);

Having given you this answer, I must implore you to find a different way to solve this problem. You cannot parse HTML using regular expressions. No matter how sophisticated your regular expression gets, there will be a legal HTML example which will break it.

edited Apr 23, 2014 at 23:44

answered Apr 23, 2014 at 23:35

Andrew Shepherd

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1 Comment

David 天宇 Wong Over a year ago

do you have a quicker solution when I just need to get .jpg ? A entire dom parser seems too heavy to me.

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