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``` git subtree add --prefix=docs/ https://github.com/gohugoio/hugoDocs.git master --squash ``` Closes #11925
45 lines
1.2 KiB
Markdown
45 lines
1.2 KiB
Markdown
---
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title: collections.IsSet
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description: Reports whether the key exists within the collection.
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categories: []
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keywords: []
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action:
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aliases: [isset]
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related:
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- functions/go-template/if
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- functions/go-template/with
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returnType: bool
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signatures: [collections.IsSet COLLECTION KEY]
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aliases: [/functions/isset]
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---
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For example, consider this site configuration:
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{{< code-toggle file=hugo >}}
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[params]
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showHeroImage = false
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{{< /code-toggle >}}
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It the value of `showHeroImage` is `true`, we can detect that it exists using either `if` or `with`:
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```go-html-template
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{{ if site.Params.showHeroImage }}
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{{ site.Params.showHeroImage }} → true
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{{ end }}
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{{ with site.Params.showHeroImage }}
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{{ . }} → true
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{{ end }}
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```
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But if the value of `showHeroImage` is `false`, we can't use either `if` or `with` to detect its existence. In this case, you must use the `isset` function:
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```go-html-template
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{{ if isset site.Params "showheroimage" }}
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<p>The showHeroImage parameter is set to {{ site.Params.showHeroImage }}.<p>
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{{ end }}
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```
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{{% note %}}
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When using the `isset` function you must reference the key using lower case. See the previous example.
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{{% /note %}}
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