List.sortBy<'T,'Key> Function (F#)

Sorts the given list using keys given by the given projection. Keys are compared using Operators.compare.

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

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

// Signature:
List.sortBy : ('T -> 'Key) -> 'T list -> 'T list (requires comparison)

// Usage:
List.sortBy projection list

Parameters

• projection
  Type: 'T -> 'Key

  The function to transform the list elements into the type to be compared.

• list
  Type: 'Tlist

  The input list.

Return Value

The sorted list.

Remarks

This is a stable sort, that is, the original order of equal elements is preserved.

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

Example

The following code example illustrates the use of List.sortBy.

let sortedList2 = List.sortBy (fun elem -> abs elem) [1; 4; 8; -2; 5]
printfn "%A" sortedList2

Output

[1; -2; 4; 5; 8]

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

Reference

Collections.List Module (F#)

Microsoft.FSharp.Collections Namespace (F#)