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Operators.( >> )<'T1,'T2,'T3> Function (F#)

Den Delimarsky|Last Updated: 7/19/2016
|
1 Contributor

Composes two functions, the function on the left being applied first

Namespace/Module Path: Microsoft.FSharp.Core.Operators

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

Syntax

// Signature:
( >> ) : ('T1 -> 'T2) -> ('T2 -> 'T3) -> 'T1 -> 'T3

// Usage:
func1 >> func2

Parameters

func1 Type: 'T1 -> 'T2

The first function to apply.

func2 Type: 'T2 -> 'T3

The second function to apply.

Return Value

The composition of the input functions.

Example

The following example demonstrates the use of the composition operator (>>).


    let append1 string1 = string1 + ".append1"
    let append2 string1 = string1 + ".append2"

    // Composition of two functions.
    let appendBoth = append1 >> append2
    printfn "%s" (appendBoth "abc")

    // Composition of three functions.
    let append3 string1 = string1 + ".append3"
    printfn "%s" ((append1 >> append2 >> append3) "abc")

    // Composition of functions with more than one parameter.
    let appendString (string1:string) (string2:string) = string1 + string2

    let appendFileExtension extension =
        appendString "." >> appendString extension
    printfn "%s" (appendFileExtension "myfile" "txt")

Output:

abc.append1.append2
abc.append1.append2.append3
myfile.txt

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

See Also

Core.Operators Module (F#)

Microsoft.FSharp.Core Namespace (F#)

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