> 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/array/arrayreduceright.md).

# ArrayReduceRight

This function iterates over every element of the array and calls the closure to work on that element.

It will reduce the array to a single value, from the right to the left, and return it.

## Method Signature

```
ArrayReduceRight(array=[array], callback=[function:BiFunction], initialValue=[any])
```

### Arguments

| Argument       | Type                  | Required | Description                                                                                                                                                                                                                                                                                     | Default |
| -------------- | --------------------- | -------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------- |
| `array`        | `array`               | `true`   | The array to reduce                                                                                                                                                                                                                                                                             |         |
| `callback`     | `function:BiFunction` | `true`   | <p>The function to invoke for each item. The function will be passed 3 arguments: the accumulator, the current item, and the<br>current index. You can alternatively pass a Java BiFunction which will only receive the first 2 args. The function should return the new accumulator value.</p> |         |
| `initialValue` | `any`                 | `false`  | The initial value of the accumulator                                                                                                                                                                                                                                                            |         |

## Examples

### Simple arrayReduceRight Example

Demonstrate how the function works from right to left.

[Run Example](https://try.boxlang.io/?code=eJw9jsEKwjAQRM%2FNVww5SAr5g1Chv9CreKjNojkklCW1DeK%2FuyboZWZY3u5sLCPzXDDgAtXpWVvRW9Wlqtfq6lSi%2FcfNX5%2FIbwtN4f7IBrHdsDAYU8HK9LQ1JTpyS8EfLcg2egxnvFTHlDdOlcepwmJCOvW20Bq9UzuHLFVxNfi%2FIOMPjtg1uQ%3D%3D)

```java
myArray = [ 
	"a",
	"b",
	"c",
	"d"
];
newArray = arrayReduceRight( myArray, ( Any prev, Any next, Any idx, Any arr ) => {
	return prev & next & idx;
}, "" );
writedump( newArray );

```

Result: d4c3b2a1

## Related

* [ArrayAppend](/boxlang-language/reference/built-in-functions/array/arrayappend.md)
* [ArrayAvg](/boxlang-language/reference/built-in-functions/array/arrayavg.md)
* [ArrayChunk](/boxlang-language/reference/built-in-functions/array/arraychunk.md)
* [ArrayClear](/boxlang-language/reference/built-in-functions/array/arrayclear.md)
* [ArrayContains](/boxlang-language/reference/built-in-functions/array/arraycontains.md)
* [ArrayContainsNoCase](/boxlang-language/reference/built-in-functions/array/arraycontainsnocase.md)
* [ArrayDelete](/boxlang-language/reference/built-in-functions/array/arraydelete.md)
* [ArrayDeleteAt](/boxlang-language/reference/built-in-functions/array/arraydeleteat.md)
* [ArrayDeleteNoCase](/boxlang-language/reference/built-in-functions/array/arraydeletenocase.md)
* [ArrayEach](/boxlang-language/reference/built-in-functions/array/arrayeach.md)
* [ArrayEvery](/boxlang-language/reference/built-in-functions/array/arrayevery.md)
* [ArrayFilter](/boxlang-language/reference/built-in-functions/array/arrayfilter.md)
* [ArrayFind](/boxlang-language/reference/built-in-functions/array/arrayfind.md)
* [ArrayFindAll](/boxlang-language/reference/built-in-functions/array/arrayfindall.md)
* [ArrayFindAllNoCase](/boxlang-language/reference/built-in-functions/array/arrayfindallnocase.md)
* [ArrayFindFirst](/boxlang-language/reference/built-in-functions/array/arrayfindfirst.md)
* [ArrayFindNoCase](/boxlang-language/reference/built-in-functions/array/arrayfindnocase.md)
* [ArrayFirst](/boxlang-language/reference/built-in-functions/array/arrayfirst.md)
* [ArrayFlatMap](/boxlang-language/reference/built-in-functions/array/arrayflatmap.md)
* [ArrayFlatten](/boxlang-language/reference/built-in-functions/array/arrayflatten.md)
* [ArrayGetMetadata](/boxlang-language/reference/built-in-functions/array/arraygetmetadata.md)
* [ArrayGroupBy](/boxlang-language/reference/built-in-functions/array/arraygroupby.md)
* [ArrayIndexExists](/boxlang-language/reference/built-in-functions/array/arrayindexexists.md)
* [ArrayInsertAt](/boxlang-language/reference/built-in-functions/array/arrayinsertat.md)
* [ArrayIsDefined](/boxlang-language/reference/built-in-functions/array/arrayisdefined.md)
* [ArrayLast](/boxlang-language/reference/built-in-functions/array/arraylast.md)
* [ArrayMap](/boxlang-language/reference/built-in-functions/array/arraymap.md)
* [ArrayMax](/boxlang-language/reference/built-in-functions/array/arraymax.md)
* [ArrayMedian](/boxlang-language/reference/built-in-functions/array/arraymedian.md)
* [ArrayMerge](/boxlang-language/reference/built-in-functions/array/arraymerge.md)
* [ArrayMid](/boxlang-language/reference/built-in-functions/array/arraymid.md)
* [ArrayMin](/boxlang-language/reference/built-in-functions/array/arraymin.md)
* [ArrayNew](/boxlang-language/reference/built-in-functions/array/arraynew.md)
* [ArrayNone](/boxlang-language/reference/built-in-functions/array/arraynone.md)
* [ArrayPop](/boxlang-language/reference/built-in-functions/array/arraypop.md)
* [ArrayPrepend](/boxlang-language/reference/built-in-functions/array/arrayprepend.md)
* [ArrayPush](/boxlang-language/reference/built-in-functions/array/arraypush.md)
* [ArrayRange](/boxlang-language/reference/built-in-functions/array/arrayrange.md)
* [ArrayReduce](/boxlang-language/reference/built-in-functions/array/arrayreduce.md)
* [ArrayReject](/boxlang-language/reference/built-in-functions/array/arrayreject.md)
* [ArrayResize](/boxlang-language/reference/built-in-functions/array/arrayresize.md)
* [ArrayReverse](/boxlang-language/reference/built-in-functions/array/arrayreverse.md)
* [ArraySet](/boxlang-language/reference/built-in-functions/array/arrayset.md)
* [ArrayShift](/boxlang-language/reference/built-in-functions/array/arrayshift.md)
* [ArraySlice](/boxlang-language/reference/built-in-functions/array/arrayslice.md)
* [ArraySome](/boxlang-language/reference/built-in-functions/array/arraysome.md)
* [ArraySort](/boxlang-language/reference/built-in-functions/array/arraysort.md)
* [ArraySplice](/boxlang-language/reference/built-in-functions/array/arraysplice.md)
* [ArraySum](/boxlang-language/reference/built-in-functions/array/arraysum.md)
* [ArraySwap](/boxlang-language/reference/built-in-functions/array/arrayswap.md)
* [ArrayToList](/boxlang-language/reference/built-in-functions/array/arraytolist.md)
* [ArrayToStruct](/boxlang-language/reference/built-in-functions/array/arraytostruct.md)
* [ArrayTranspose](/boxlang-language/reference/built-in-functions/array/arraytranspose.md)
* [ArrayUnique](/boxlang-language/reference/built-in-functions/array/arrayunique.md)
* [ArrayUnshift](/boxlang-language/reference/built-in-functions/array/arrayunshift.md)
* [ArrayZip](/boxlang-language/reference/built-in-functions/array/arrayzip.md)


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