Array.reduceBack<'T> Function (F#)
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 i0 (...(f iN-1 iN)). Raises ArgumentException if the array has size zero.
Namespace/Module Path: Microsoft.FSharp.Collections.Array
Assembly: FSharp.Core (in FSharp.Core.dll)
// Signature:
Array.reduceBack : ('T -> 'T -> 'T) -> 'T [] -> 'T
// Usage:
Array.reduceBack reduction array
Parameters
reduction
Type: 'T -> 'T -> 'TThe function to reduce a pair of elements to a single element.
array
Type: 'T[]The input array.
Exceptions
Exception |
Condition |
|---|---|
Thrown when the input array is empty. |
Return Value
The final result of the reductions.
Remarks
This function is named ReduceBack in compiled assemblies. If you are accessing the member from a language other than F#, or through reflection, use this name.
Example
The following code example compares Array.reduce and Array.reduceBack.
// Computes ((1 - 2) - 3) - 4 = -8
Array.reduce (fun elem acc -> elem - acc) [| 1; 2; 3; 4 |]
|> printfn "%A"
// Computes 1 - (2 - (3 - 4)) = -2
Array.reduceBack (fun elem acc -> elem - acc) [| 1; 2; 3; 4 |]
|> printfn "%A"
Output
-8 -2
Platforms
Windows 8, Windows 7, Windows Server 2012, Windows Server 2008 R2
Version Information
F# Core Library Versions
Supported in: 2.0, 4.0, Portable