> For the complete documentation index, see [llms.txt](https://boxlang.ortusbooks.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://boxlang.ortusbooks.com/boxlang-language/reference/built-in-functions/struct/structkeyexists.md).

# StructKeyExists

Tests whether a key exists in a struct and returns a boolean value

## Method Signature

```
StructKeyExists(struct=[structloose], key=[any])
```

### Arguments

| Argument | Type     | Required | Description                                     | Default |
| -------- | -------- | -------- | ----------------------------------------------- | ------- |
| `struct` | `struct` | `true`   | The struct to test                              |         |
| `key`    | `any`    | `true`   | The key within the struct to test for existence |         |

## Examples

### Check if server struct has OS key

[Run Example](https://try.boxlang.io/?code=eJwrLikqTS7xTq10rcgsLinWUChOLSpLLdJRUMovVlLQtOYCANfYCy4%3D)

```java
structKeyExists( server, "os" );

```

Result: true

### Check if server struct has OS key using member function

Calling the keyExists member function on a struct.

[Run Example](https://try.boxlang.io/?code=eJwrTi0qSy3Sy06tdK3ILC4p1lBQyi9WUtC05gIAhJEIiw%3D%3D)

```java
server.keyExists( "os" );

```

Result: true

### Additional Examples

[Run Example](https://try.boxlang.io/?code=eJxdjs0KgkAUhdfOUxxmo4HgPmlRFiFBRQmth%2BGKgzoTjlEivnuOCUXczf04PxyhVS0qixV6MC853bAEr43hIfPO6d6RUbp0mKyzSSTzdLhJL1vHslDNnbMhZlGEpCBZojWwRFA5SupAL2VbC6Vh2%2BYhW6byANfpPVC3m9QA4jMkBLdaqIpjMV7PPJKFCcCzgpqx0UJg0l2dP2f80RyzgYEqSz%2BZo5m93wX%2FkTfpU0v8)

```java
animals = { 
	COW : "moo",
	PIG : "oink",
	CAT : "meow",
	BIRD : "chirp"
};
// Check to see if key exists in struct
if( StructKeyExists( animals, "snail" ) ) {
	echo( "There is a snail in 'animals'" );
}
 else {
	echo( "No snail exists in 'animals'" );
}

```

## Related

* [StructAppend](/boxlang-language/reference/built-in-functions/struct/structappend.md)
* [StructClear](/boxlang-language/reference/built-in-functions/struct/structclear.md)
* [StructCopy](/boxlang-language/reference/built-in-functions/struct/structcopy.md)
* [StructDelete](/boxlang-language/reference/built-in-functions/struct/structdelete.md)
* [StructEach](/boxlang-language/reference/built-in-functions/struct/structeach.md)
* [StructEquals](/boxlang-language/reference/built-in-functions/struct/structequals.md)
* [StructEvery](/boxlang-language/reference/built-in-functions/struct/structevery.md)
* [StructFilter](/boxlang-language/reference/built-in-functions/struct/structfilter.md)
* [StructFind](/boxlang-language/reference/built-in-functions/struct/structfind.md)
* [StructFindKey](/boxlang-language/reference/built-in-functions/struct/structfindkey.md)
* [StructFindValue](/boxlang-language/reference/built-in-functions/struct/structfindvalue.md)
* [StructGet](/boxlang-language/reference/built-in-functions/struct/structget.md)
* [StructGetMetadata](/boxlang-language/reference/built-in-functions/struct/structgetmetadata.md)
* [StructInsert](/boxlang-language/reference/built-in-functions/struct/structinsert.md)
* [StructIsCaseSensitive](/boxlang-language/reference/built-in-functions/struct/structiscasesensitive.md)
* [StructIsOrdered](/boxlang-language/reference/built-in-functions/struct/structisordered.md)
* [StructKeyArray](/boxlang-language/reference/built-in-functions/struct/structkeyarray.md)
* [StructKeyList](/boxlang-language/reference/built-in-functions/struct/structkeylist.md)
* [StructKeyTranslate](/boxlang-language/reference/built-in-functions/struct/structkeytranslate.md)
* [StructMap](/boxlang-language/reference/built-in-functions/struct/structmap.md)
* [StructNew](/boxlang-language/reference/built-in-functions/struct/structnew.md)
* [StructNone](/boxlang-language/reference/built-in-functions/struct/structnone.md)
* [StructReduce](/boxlang-language/reference/built-in-functions/struct/structreduce.md)
* [StructSome](/boxlang-language/reference/built-in-functions/struct/structsome.md)
* [StructSort](/boxlang-language/reference/built-in-functions/struct/structsort.md)
* [StructToQueryString](/boxlang-language/reference/built-in-functions/struct/structtoquerystring.md)
* [StructToSorted](/boxlang-language/reference/built-in-functions/struct/structtosorted.md)
* [StructUpdate](/boxlang-language/reference/built-in-functions/struct/structupdate.md)
* [StructValueArray](/boxlang-language/reference/built-in-functions/struct/structvaluearray.md)


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