isset.md (1139B)
1 ---
2 title: isset
3 linktitle: isset
4 description: Returns true if the parameter is set.
5 date: 2017-02-01
6 publishdate: 2017-02-01
7 lastmod: 2017-02-01
8 categories: [functions]
9 menu:
10 docs:
11 parent: "functions"
12 keywords: []
13 signature: ["isset COLLECTION INDEX", "isset COLLECTION KEY"]
14 workson: []
15 hugoversion:
16 relatedfuncs: []
17 deprecated: false
18 aliases: []
19 ---
20
21 Takes either a slice, array, or channel and an index or a map and a key as input.
22
23 ```
24 {{ if isset .Params "project_url" }} {{ index .Params "project_url" }}{{ end }}
25 ```
26
27 {{% warning %}}
28 All site-level configuration keys are stored as lower case. Therefore, a `myParam` key-value set in your [site configuration file](/getting-started/configuration/) needs to be accessed with `{{if isset .Site.Params "myparam"}}` and *not* with `{{if isset .Site.Params "myParam"}}`. Note that you can still access the same config key with `.Site.Params.myParam` *or* `.Site.Params.myparam`, for example, when using [`with`](/functions/with).
29 This restriction also applies when accessing page-level front matter keys from within [shortcodes](/content-management/shortcodes/).
30 {{% /warning %}}