Table of contents
Collapse the table of content
Expand the table of content

Array.exists2<'T1,'T2> Function (F#)

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

Tests if any pair of corresponding elements of the arrays satisfies the given predicate.

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

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


// Signature:
Array.exists2 : ('T1 -> 'T2 -> bool) -> 'T1 [] -> 'T2 [] -> bool

// Usage:
Array.exists2 predicate array1 array2


predicate Type: 'T1 -> 'T2 ->bool

The function to test the input elements.

array1 Type: 'T1[]

The first input array.

array2 Type: 'T2[]

The second input array.

Return value

true if any result from predicate is true. Otherwise, false.


The predicate is applied to matching elements in the two collections up to the lesser of the two lengths of the collections. If any application returns true then the overall result is true and no further elements are tested. Otherwise, if one collection is longer than the other then the ArgumentException exception is raised. Otherwise, false is returned.

This function is named Exists2 in compiled assemblies. If you are accessing the member from a language other than F#, or through reflection, use this name.


The following example shows the use Array.exists2 to test whether two arrays have at least one equal element.

let haveEqualElement = Array.exists2 (fun elem1 elem2 -> elem1 = elem2)
printfn "%A" (haveEqualElement [| 1; 2; 3 |] [| 3; 2; 1|])


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#)

© 2020 Microsoft