Making regex less inclusive

Question

I have a regex I'm trying to get out of a string. It seems to be including way too much. Here's my code.

preg_match_all('/<li class="has-activity"><a class="group-entity" 
href="(.*?)"><span class="activity-count">(.*)<\/span><span 
class="image"><img alt="(.*?)" src/i',$output,$matches);

I JUST want it to grab the stuff as seen in (.*?) , but it seems to want to grab more.

MORE INFO:

Here's an example of what I'm trying to extract from. This is just one entity though. (Using preg_match_all)

<li class="has-activity"><a class="group-entity" href="/grp/home?gid=2813868&amp;trk=my_groups-tile-grp">
<span class="activity-count">7</span>
<span class="image"><img alt="[Rated #1 in Marketing] The Social Media Marketing Group" src

The two main things I need to grab is the group href ("/grp/home?gid=2813868&trk=my_groups-tile-grp" in this instance) and the group name (the thing between the alt tag. "[Rated #1 in Marketing] The Social Media Marketing Group" in this case)

With my updated code of (.?*), it seems to be grabbing the NAME just fine. But I can't properly grab the href of the group.

give some examples please of text and what you need to extract and how it fails? — Nikos M., Aug 17 '15 at 21:31
Don't use regex to parse html, just don't. It will never work and will have an infinite number of problems. Instead try php domdocument — Downgoat, Aug 17 '15 at 21:41
If you want `(.*)` to act as `(.*?)` why not use `(.*?)`? A parser would be far more reliable. Without seeing what you are running this on it is hard to say why it is failing. — chris85, Aug 17 '15 at 21:44
Yeah. I tried to use (.*?) and it's still not working. When using (.*?) , it grabs — user1687621, Aug 17 '15 at 21:47
please specify along with the sample xml what you need to extract — Nikos M., Aug 17 '15 at 21:49
you might have a problem with *greediness* (the default mode for regex) — hoijui, Aug 17 '15 at 21:50

Nikos M. · Accepted Answer · 2015-08-17T22:04:58.950

2

For starters since .* seem to match attributes they can be replaced with [^"]*

i.e

preg_match_all('/<li class="has-activity"><a class="group-entity" 
href="([^"]*)"><span class="activity-count">(.*)<\/span><span 
class="image"><img alt="([^"]*)"/i',$output,$matches);

if inside span there are no more tags, just text you can also use

preg_match_all('/<li class="has-activity"><a class="group-entity" 
href="([^"]*)"><span class="activity-count">([^<]*)<\/span><span 
class="image"><img alt="([^"]*)"/i',$output,$matches);

this is exact and will not match more nor override elements and attributes, although (general) xml/html parsing is not easy using just regular expressions

update

html sample code

<li class="has-activity"><a class="group-entity" href="/grp/home?gid=2813868&amp;trk=my_groups-tile-grp"><span class="activity-count">6</span><span class="image"><img alt="[Rated #1 in Marketing] The Social Media Marketing Group" src

<a class="group-entity" href="LINK" and the alt of that img tag need to be extracted

use following

preg_match_all('/<li.*?class="has-activity".*?href="([^"]*)".*?<img.*?alt="([^"]*)"/i',$output,$matches);

try not to use preg_match_all and if neded add the multiline flag (i.e '/../m') plus if more refined matching is needed use an xml parser (as suggested)

edited Aug 17 '15 at 22:04

answered Aug 17 '15 at 21:35

Nikos M.

8,033
4
36
43

That doesn't work at all. – user1687621 Aug 17 '15 at 21:39
can you give some examples please of text and what is expected to match? i already made this comment above, to see how it fails – Nikos M. Aug 17 '15 at 21:41
So here's an example of a thing I'm trying to grab from.
6

user1687621

Aug 17 '15 at 21:43

Update your question with the code sample. – chris85 Aug 17 '15 at 21:46

and you need to extract what exactly? – Nikos M. Aug 17 '15 at 21:48

@user1687621, ok updating my answer with xml sample and extraction – Nikos M. Aug 17 '15 at 21:50

Updated explanation in my question. – user1687621 Aug 17 '15 at 21:54

@user1687621 updated my answer – Nikos M. Aug 17 '15 at 21:59

score 1 · Answer 2 · answered Aug 17 '15 at 22:11

preg_match_all('<li class="has\-activity"><a class="group\-entity" href=(.*?)"><span class="activity\-count">([0-9]+)<\/span><span class="image"><img alt="(.*)" src/i',$output,$matches);

Regex isn't the best tool for extracting html. It can get very messy. I find jQuery extremely useful for extracting html content, and then if I need to, I can perform string operations on it in PHP afterwards.

The reason why regular expressions are so tricky with html is edge cases. A slight change to the html could break the entire regular expression.

Making regex less inclusive

2 Answers2