# StructReduce

Run the provided udf against struct to reduce the values to a single output

## Method Signature

```
StructReduce(struct=[structloose], callback=[function], initialValue=[any])
```

### Arguments

| Argument       | Type       | Required | Description                                                                                                                                                                                                                                   | Default |
| -------------- | ---------- | -------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------- |
| `struct`       | `struct`   | `true`   | The struct to reduce                                                                                                                                                                                                                          |         |
| `callback`     | `function` | `true`   | <p>The function to invoke for each entry in the struct. The function will be passed 4 arguments: the accumulator, they entry key,<br>the<br>current index, and the original struct. The function should return the new accumulator value.</p> |         |
| `initialValue` | `any`      | `false`  | The initial value of the accumulator                                                                                                                                                                                                          |         |

## Examples

### Script Syntax

[Run Example](https://try.boxlang.io/?code=eJxVjkGrwjAQhM%2FmVywpPFooeLc1IAgePAgelHfMM8sztCZlzVpE%2FO8mqQjeZj9mZoe0dX9%2BhCU8QMzkHo2EBcjjGcnLOpIdafePGW416U5n%2Bot978eJ%2BvGsbaYbQnRva6fJdlaKZyPYxvprID6F2M8nLIGmtzWUsHJ3GAhv1vP1oHvGOqMO75O4JQYVLBU8xIwwMLnvAPyAbE1QRcwU7Tyq1hhV5GC6jZKNeNbJ1CsZq5J%2FnnQjRrIB13wZPpugetMdh4FDCXF%2BRC%2BVH1oX)

```java
rainbow = { 
	"Red" : "Whero",
	"Orange" : "Karaka",
	"Yellow" : "Kowhai",
	"Green" : "Kakariki"
};
ui = structReduce( rainbow, ( Any previousValue, Any key, Any value ) => {
	return previousValue & "<dt>#key#</dt><dd>#value#</dd>";
}, "<dl>" ) & "</dl>";
writeDump( rainbow );
writeOutput( ui );

```

### Using Member Function

[Run Example](https://try.boxlang.io/?code=eJxVjsEKwjAQRM%2FmK5YUpELRu60BQfDgQfCgeIxm0dCalDWxlOK%2Fm6R68Db7mJkdktpcbAcrGIBN%2BAEVhyXw0x3J8iKQPUlzwwR3kmQtEz1j09hupLa7S53olhDN11pL0rXm7F0yr0M9jY%2FmhMpfMYcc1qaHlvClrX8eZeOxSKjGfhSvyGAGKwEDmxA6T%2BY%2FAFPglXIiC5msWgRVKSWyFIy3Erxk7yKaGsFDVfQvoi5ZR9rhxj%2Fa%2FDcNZl%2B69671LoewO6AP1rdXdA%3D%3D)

```java
rainbow = { 
	"Red" : "Whero",
	"Orange" : "Karaka",
	"Yellow" : "Kowhai",
	"Green" : "Kakariki"
};
ui = rainbow.reduce( ( Any previousValue, Any key, Any value ) => {
	return previousValue & "<dt>#key#</dt><dd>#value#</dd>";
}, "<dl>" ) & "</dl>";
writeDump( rainbow );
writeOutput( ui );

```

### Additional Examples

[Run Example](https://try.boxlang.io/?code=eJx1kNFLwzAQxp%2Bbv%2BLIg3RQ1ndrB2UUKY5N1k2Zb7E9XVjaSNpszNH%2F3STtlCq%2BfZf73eX7jtW8YqKBGC5AvPnqGW7hQjxvucry1GhaSUkD85BnL64WTL0jJV5nHh%2Bz%2B9%2B45PVhxFdYcl0NA%2FNk82c%2FytNooDF%2BhOVJF5FSVx8%2BCPaKIqaJEMB6vzSAI1PxUMEkIr3M6jdpsuSt0kW7xlIX6F9nAvAhqc%2BgsNGiDZw%2B4LkXRyY0wgTimbWnsNWqBhNVV1i3zXSd5tvFBm6A3gk%2Bo0b89B7SnWtoMbPNpeQNmhwj5ilZbNNpH9qyoQEtnPPPf1h3jm80tMutohHpgv4zauw6wOqIhCHke3ka4hEs9vIa3V3F3OgLFw2MlQ%3D%3D)

```java
animals = { 
	COW : {
		NOISE : "moo",
		SIZE : "large"
	},
	PIG : {
		NOISE : "oink",
		SIZE : "medium"
	},
	CAT : {
		NOISE : "meow",
		SIZE : "small"
	}
};
dump( label="All animals", var=animals );
animalInfo = StructReduce( animals, ( Any result, Any key, Any value ) => {
	return arguments.RESULT & "<li>" & arguments.KEY & "<ul><li>Noise: " & arguments.VALUE.NOISE & "</li><li>Size: " & arguments.VALUE.SIZE & "</li></ul></li>";
}, "<ul>" ) & "</ul>";
// Show result
echo( animalInfo );

```

## 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)
* [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)


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://boxlang.ortusbooks.com/boxlang-language/reference/built-in-functions/struct/structreduce.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.