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Map.forall<'Key,'T> Function (F#)

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

Returns true if the given predicate returns true for all of the bindings in the map.

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

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


// Signature:
Map.forall : ('Key -> 'T -> bool) -> Map<'Key,'T> -> bool (requires comparison)

// Usage:
Map.forall predicate table


predicate Type: 'Key -> 'T ->bool

The function to test the input elements.

table Type: Map<'Key,'T>

The input map.

Return Value

true if the predicate evaluates to true for all of the bindings in the map.


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


let map1 = Map.ofList [ (1, "one"); (2, "two"); (3, "three") ]
let map2 = Map.ofList [ (-1, "negative one"); (2, "two"); (3, "three") ]
let allPositive = Map.forall (fun key value -> key > 0)
printfn "%b %b" (allPositive map1) (allPositive map2)


true false


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.Map Module (F#)

Microsoft.FSharp.Collections Namespace (F#)

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