> 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/structupdate.md).

# StructUpdate

Updates or sets a key/value pair in to a struct

## Method Signature

```
StructUpdate(struct=[modifiableStruct], key=[any], value=[any])
```

### Arguments

| Argument | Type               | Required | Description                               | Default |
| -------- | ------------------ | -------- | ----------------------------------------- | ------- |
| `struct` | `modifiableStruct` | `true`   | The target struct                         |         |
| `key`    | `any`              | `true`   | The struct key                            |         |
| `value`  | `any`              | `true`   | The value to assign for the specified key |         |

## Examples

### Updates a structure value at specific key

Change value of structure item

[Run Example](https://try.boxlang.io/?code=eJzLrQwuKSpNLlGwVahW4OJ0VLBSMNTh4nQC0kZA2hlIGwNpFyBtwlVrzVUMVh1akJJYkqqhkAvVraOglKyko2BoqqBpzVVelFmS6lKaW6Ch4BXs7xecWpSZmJNZhaRcQROkDgDFciI%2F)

```java
myStruct = { 
	A : 1,
	B : 2,
	C : 3,
	D : 4
};
structUpdate( myStruct, "c", 15 );
writeDump( JSONSerialize( myStruct ) );

```

Result: {"A":1,"B":2,"C":15,"D":4}

### Additional Examples

[Run Example](https://try.boxlang.io/?code=eJxljk0LgjAcxs%2FuUzz8TwaC98KDGESnAovOSweOdJO15SH67unUyDo%2Bbz8ermTD6zsSPMGC7HDBGtRoTRELjvvdoLRUt0Fm6cmHQnfEXhsWx8gr3aFwxghlwUcU27qmDVHzq6gTypYhRXhwk0wKK085tyW3AgW3kOqDya1xhR2zcHYjUF%2FrKdT2YJoA%2FsbM7KSt4Pys%2FGUurqXfg6E4jf4%2FvgHMuF3T)

```java
animals = { 
	COW : "moo",
	PIG : "oink",
	CAT : "meow"
};
// Show current animals
Dump( label="Current animals", var=animals );
// Update cat in animals
StructUpdate( animals, "cat", "purr" );
// Show animals with updated cat in animals
Dump( label="Animals with cat updated", var=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)
* [StructKeyExists](/boxlang-language/reference/built-in-functions/struct/structkeyexists.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)
* [StructValueArray](/boxlang-language/reference/built-in-functions/struct/structvaluearray.md)


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