Enumerable.Take<TSource> Method
Microsoft Silverlight will reach end of support after October 2021. Learn more.
Returns a specified number of contiguous elements from the start of a sequence.
Namespace: System.Linq
Assembly: System.Core (in System.Core.dll)
Syntax
'Declaration
<ExtensionAttribute> _
Public Shared Function Take(Of TSource) ( _
source As IEnumerable(Of TSource), _
count As Integer _
) As IEnumerable(Of TSource)
public static IEnumerable<TSource> Take<TSource>(
this IEnumerable<TSource> source,
int count
)
Type Parameters
- TSource
The type of the elements of source.
Parameters
- source
Type: System.Collections.Generic.IEnumerable<TSource>
The sequence to return elements from.
- count
Type: System.Int32
The number of elements to return.
Return Value
Type: System.Collections.Generic.IEnumerable<TSource>
An IEnumerable<T> that contains the specified number of elements from the start of the input sequence.
Usage Note
In Visual Basic and C#, you can call this method as an instance method on any object of type IEnumerable<TSource>. When you use instance method syntax to call this method, omit the first parameter.
Exceptions
| Exception | Condition |
|---|---|
| ArgumentNullException | source is nulla null reference (Nothing in Visual Basic). |
Remarks
This method is implemented by using deferred execution. The immediate return value is an object that stores all the information that is required to perform the action. The query represented by this method is not executed until the object is enumerated either by calling its GetEnumerator method directly or by using foreach in Visual C# or For Each in Visual Basic.
Take<TSource> enumerates source and yields elements until count elements have been yielded or source contains no more elements.
If count is less than or equal to zero, source is not enumerated and an empty IEnumerable<T> is returned.
The Take<TSource> and Skip<TSource> methods are functional complements. Given a sequence coll and an integer n, concatenating the results of coll.Take(n) and coll.Skip(n) yields the same sequence as coll.
In Visual Basic query expression syntax, a Take clause translates to an invocation of Take<TSource>.
Examples
The following code example demonstrates how to use Take<TSource> to return elements from the start of a sequence.
' Create an array of Integer values that represent grades.
Dim grades() As Integer = {59, 82, 70, 56, 92, 98, 85}
' Get the highest three grades by first sorting
' them in descending order and then taking the
' first three values.
Dim topThreeGrades As IEnumerable(Of Integer) = _
grades _
.OrderByDescending(Function(grade) grade) _
.Take(3)
' Display the results.
Dim output As New System.Text.StringBuilder("The top three grades are:" & vbCrLf)
For Each grade As Integer In topThreeGrades
output.AppendLine(grade)
Next
outputBlock.Text &= output.ToString() & vbCrLf
' This code produces the following output:
'
' The top three grades are:
' 98
' 92
' 85
int[] grades = { 59, 82, 70, 56, 92, 98, 85 };
IEnumerable<int> topThreeGrades =
grades.OrderByDescending(grade => grade).Take(3);
outputBlock.Text += "The top three grades are:" + "\n";
foreach (int grade in topThreeGrades)
{
outputBlock.Text += grade + "\n";
}
/*
This code produces the following output:
The top three grades are:
98
92
85
*/
Version Information
Silverlight
Supported in: 5, 4, 3
Silverlight for Windows Phone
Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0
XNA Framework
Supported in: Xbox 360, Windows Phone OS 7.0
Platforms
For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.