Regex for Finding classes in HTML files

Question

I have a bunch of HTML files I need to search to find where a class name is used in the application.

Ex1: should match both of these:

<div class="something else field">Foo</div>
<span class="field">Bar</span>

Ex2: should not match

<div class="baseball-field baz">Baz</div>

I need a pattern to find a class name in my files

What I've tried is: /class(?=field)/

But this doesn't work, I'm not sure how to account for possible other characters in the search.

Update:

I tried: class.*(?=field), that works for Ex1 but not 2

Have you considered other ways besides Regex? E.g. https://stackoverflow.com/a/10585079/2798367 — ne1410s, Aug 18 '17 at 14:52

Federico Piazza · Accepted Answer · 2017-08-18T15:10:51.147

1

Your regex is almost correct but you want to search for class="field" while your regex just check for classfield.

So, you can use this regex instead:

class(?=="field")

In addition, not sure what tool/language you are using, but consider using an html parser instead or xpath/xquery instead.

Update: since you updated your question, here I provided the updates for the answer. You could use this regex instead:

class(?=="(?:field|.*?\sfield|field\s.*?)")

Btw, if you want to merge above alternations you could use:

class(?=="(?:(?:.*?\s)?field(?:\s.*?)?)")

You could clean up a bit the regex above removing the non-capturing groups to

class(?=="((.*?\s)?field(\s.*?)?)")

edited Aug 18 '17 at 15:10

answered Aug 18 '17 at 15:01

Federico Piazza

Thanks for the answer, this works great for when the class is exactly one value, but what about when there are multiple classes in the string and I'm looking for one? – SoluableNonagon Aug 18 '17 at 15:03
I tried `class.*(?=field)` but it's matches on too much; like class="baseball-field" – SoluableNonagon Aug 18 '17 at 15:04

score 0 · Answer 2 · answered Mar 04 '21 at 19:28

The accepted answer is close, but is missing one fourth important case:

Here is the RegExp that is true for each of the above cases, but false if anything other than a space or quotation mark is next to the 'field' class:

class(?=="(?:field|.*?\sfield|field\s.*?|.*?\sfield\s.*?)")

2 Answers2