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

Applies a key-generating function to each element of a sequence and yields a sequence ordered by keys. The keys are compared using generic comparison as implemented by Operators.compare.

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

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

// Signature:
Seq.sortBy : ('T -> 'Key) -> seq<'T> -> seq<'T> (requires comparison)

// Usage:
Seq.sortBy projection source

Parameters

• projection
  Type: 'T -> 'Key

  A function to transform items of the input sequence into comparable keys.

• source
  Type: seq<'T>

  The input sequence.

Exceptions

Exception	Condition
ArgumentNullException	Thrown when the input sequence is null.

Return Value

The result sequence.

Remarks

This function returns a sequence that digests the whole initial sequence as soon as that sequence is iterated. Therefore, this function should not be used with large or infinite sequences. The function makes no assumption on the ordering of the original sequence. 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.

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.Seq Module (F#)

Microsoft.FSharp.Collections Namespace (F#)