Seq.take<'T> Function (F#)
Returns the elements of the sequence up to a specified count.
Namespace/Module Path: Microsoft.FSharp.Collections.Seq
Assembly: FSharp.Core (in FSharp.Core.dll)
// Signature:
Seq.take : int -> seq<'T> -> seq<'T>
// Usage:
Seq.take count source
Parameters
Exceptions
Exception |
Condition |
|---|---|
Thrown when the input sequence is empty. |
|
Thrown when the input sequence is null. |
|
Thrown when count exceeds the number of elements in the sequence. |
Return Value
The result sequence.
Remarks
Seq.truncate returns as many items as the sequence contains instead of throwing an exception.
This function is named Take in compiled assemblies. If you are accessing the function from a language other than F#, or through reflection, use this name.
Example
The following example demonstrates the use of Seq.take and contrasts the behavior with Seq.truncate.
let mySeq = seq { for i in 1 .. 10 -> i*i }
let truncatedSeq = Seq.truncate 5 mySeq
let takenSeq = Seq.take 5 mySeq
let truncatedSeq2 = Seq.truncate 20 mySeq
let takenSeq2 = Seq.take 20 mySeq
let printSeq seq1 = Seq.iter (printf "%A ") seq1; printfn ""
// Up to this point, the sequences are not evaluated.
// The following code causes the sequences to be evaluated.
truncatedSeq |> printSeq
truncatedSeq2 |> printSeq
takenSeq |> printSeq
// The following line produces a run-time error (in printSeq):
takenSeq2 |> printSeq
1 4 9 16 25 1 4 9 16 25 36 49 64 81 100 1 4 9 16 25 1 4 9 16 25 36 49 64 81 100
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