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Array.reduce<'T> Function (F#)

Den Delimarsky|Last Updated: 8/18/2017
1 Contributor

Applies a function to each element of the array, threading an accumulator argument through the computation. If the input function is f and the elements are i0...iN, then computes f (... (f i0 i1)...) iN. Raises System.ArgumentException if the array has size zero.

Namespace/Module Path: Microsoft.FSharp.Collections.Array

Assembly: FSharp.Core (in FSharp.Core.dll)


// Signature:
Array.reduce : ('T -> 'T -> 'T) -> 'T [] -> 'T

// Usage:
Array.reduce reduction array


reduction Type: 'T -> 'T -> 'T

The function to reduce a pair of elements to a single element.

array Type: 'T[]

The input array.

Return Value

Returns the final result of the reductions.


This function is named Reduce in compiled assemblies. If you are accessing the function from a language other than F#, or through reflection, use this name.


The following example demonstrates the use of Array.reduce.

let names = [| "A"; "man"; "landed"; "on"; "the"; "moon" |]
let sentence = names |> Array.reduce (fun acc item -> acc + " " + item)
printfn "sentence = %s" sentence


sentence = A man landed on the moon


Windows 8, Windows 7, Windows Server 2012, Windows Server 2008 R2

Version Information

F# Core Library Versions

Supported in: 2.0, 4.0, Portable

See Also

Collections.Array Module (F#)

Microsoft.FSharp.Collections Namespace (F#)

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