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List.isEmpty<'T> Function (F#)

Tests whether a list is empty.

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

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

// Signature:
List.isEmpty : 'T list -> bool

// Usage:
List.isEmpty list

list

Type: 'T list

The input list.

true if the list is empty. Otherwise, returns false.

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

The following code shows how to use List.isEmpty.

let printList list1 = 
    if (List.isEmpty list1) then
        printfn "There are no elements in this list." 
    else
        printfn "This list contains the following elements:"
        List.iter (fun elem -> printf "%A " elem) list1
        printfn ""
printList [ "test1"; "test2" ]
printList [ ]

Output

This list contains the following elements:
"test1" "test2" 
There are no elements in this list.

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

F# Core Library Versions

Supported in: 2.0, 4.0, Portable

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