replacere.md (1397B)
1 ---
2 title: replaceRE
3 description: Replaces all occurrences of a regular expression with the replacement pattern.
4 date: 2017-02-01
5 publishdate: 2017-02-01
6 lastmod: 2020-09-07
7 categories: [functions]
8 menu:
9 docs:
10 parent: "functions"
11 keywords: [regex]
12 signature: ["strings.ReplaceRE PATTERN REPLACEMENT INPUT [LIMIT]", "replaceRE PATTERN REPLACEMENT INPUT [LIMIT]"]
13 workson: []
14 hugoversion:
15 relatedfuncs: []
16 deprecated: false
17 aliases: []
18 ---
19
20 `strings.ReplaceRE` returns a copy of `INPUT`, replacing all matches of the regular
21 expression `PATTERN` with the replacement text `REPLACEMENT`.
22 The number of replacements can be limited with an optional `LIMIT` parameter.
23
24 ```
25 {{ replaceRE "^https?://([^/]+).*" "$1" "http://gohugo.io/docs" }}` → "gohugo.io"
26 {{ "http://gohugo.io/docs" | replaceRE "^https?://([^/]+).*" "$1" }}` → "gohugo.io"
27 {{ replaceRE "a+b" "X" "aabbaabbab" 1 }} → "Xbaabbab"
28 ```
29
30 {{% note %}}
31 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).
32
33 If you are just learning RegEx, or at least Go's flavor, you can practice pattern matching in the browser at <https://regex101.com/>.
34 {{% /note %}}