The example below returns a list of all second level headers (`<h2>`) in the content:
```
{{ findRE "<h2.*?>(.|\n)*?</h2>" .Content }}
```
You can limit the number of matches in the list with a third parameter. The following example shows how to limit the returned value to just one match (or none, if there are no matched substrings):
```
{{ findRE "<h2.*?>(.|\n)*?</h2>" .Content 1 }}
<!-- returns ["<h2 id="#foo">Foo</h2>"] -->
```
{{% note %}}
Hugo uses Go's [Regular Expression package](https://golang.org/pkg/regexp/), which is the same general syntax used by Perl, Python, and other languages but with a few minor differences for those coming from a background in PCRE. For a full syntax listing, see the [GitHub wiki for re2](https://github.com/google/re2/wiki/Syntax).
If you are just learning RegEx, or at least Go's flavor, you can practice pattern matching in the browser at <https://regex101.com/>.
