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Diffstat (limited to 'docs/content/en/functions/findRe.md')
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diff --git a/docs/content/en/functions/findRe.md b/docs/content/en/functions/findRe.md index b6375be9c..2896e3cd1 100644 --- a/docs/content/en/functions/findRe.md +++ b/docs/content/en/functions/findRe.md @@ -1,44 +1,40 @@ --- title: findRE -description: Returns a list of strings that match the regular expression. -date: 2017-02-01 -publishdate: 2017-02-01 -lastmod: 2017-02-01 +description: Returns a slice of strings that match the regular expression. categories: [functions] menu: docs: - parent: "functions" + parent: functions keywords: [regex] -signature: ["findRE PATTERN INPUT [LIMIT]"] -workson: [] -hugoversion: -relatedfuncs: [] -deprecated: false +signature: + - "findRE PATTERN INPUT [LIMIT]" + - "strings.FindRE PATTERN INPUT [LIMIT]" +relatedfuncs: [replaceRE] aliases: [] --- +By default, the `findRE` function finds all matches. You can limit the number of matches with an optional LIMIT paramater. -By default all matches will be included. The number of matches can be limited with an optional third parameter. +When specifying the regular expression, use a raw [string literal] (backticks) instead of an interpreted string literal (double quotes) to simplify the syntax. With an interpreted string literal you must escape backslashes. -The example below returns a list of all second level headers (`<h2>`) in the content: +The syntax of the regular expression is the same general syntax used by Perl, Python, and other languages. More precisely, it is the syntax accepted by [RE2] except for `\C`. -``` -{{ findRE "<h2.*?>(.|\n)*?</h2>" .Content }} +This example returns a slice of all second level headings (`h2` elements) within the rendered `.Content`: + +```go-html-template +{{ findRE `(?s)<h2.*?>.*?</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): +The `s` flag causes `.` to match `\n` as well, allowing us to find an `h2` element that contains newlines. -``` -{{ findRE "<h2.*?>(.|\n)*?</h2>" .Content 1 }} - <!-- returns ["<h2 id="#foo">Foo</h2>"] --> +To limit the number of matches to one: + +```go-html-template +{{ findRE `(?s)<h2.*?>.*?</h2>` .Content 1 }} ``` {{% 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/>. +You can write and test your regular expression using [regex101.com](https://regex101.com/). Be sure to select the Go flavor before you begin. {{% /note %}} -[partials]: /templates/partials/ -[`plainify`]: /functions/plainify/ -[toc]: /content-management/toc/ -[`urlize`]: /functions/urlize +[RE2]: https://github.com/google/re2/wiki/Syntax +[string literal]: https://go.dev/ref/spec#String_literals |