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Array.ForEach<T>(T[], Action<T>) Method

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Definition

Namespace:
System
Assembly:
System.Runtime.dll
Assembly:
mscorlib.dll
Assembly:
netstandard.dll
Source:
Array.cs
Source:
Array.cs
Source:
Array.cs

Performs the specified action on each element of the specified array.

public:
generic <typename T>
 static void ForEach(cli::array <T> ^ array, Action<T> ^ action);
public static void ForEach<T> (T[] array, Action<T> action);
static member ForEach : 'T[] * Action<'T> -> unit
Public Shared Sub ForEach(Of T) (array As T(), action As Action(Of T))

Type Parameters

T

The type of the elements of the array.

Parameters

array
T[]

The one-dimensional, zero-based Array on whose elements the action is to be performed.

action
Action<T>

The Action<T> to perform on each element of array.

Exceptions

ArgumentNullException

array is null.

-or-

action is null.

Examples

The following example shows how to use ForEach to display the squares of each element in an integer array.

using namespace System;

public ref class SamplesArray
{
public:
    static void Main()
    {
        // create a three element array of integers
        array<int>^ intArray = gcnew array<int> {2, 3, 4};

        // set a delegate for the ShowSquares method
        Action<int>^ action = gcnew Action<int>(ShowSquares);

        Array::ForEach(intArray, action);
    }

private:
    static void ShowSquares(int val)
    {
        Console::WriteLine("{0:d} squared = {1:d}", val, val*val);
    }
};

int main()
{
    SamplesArray::Main();
}

/*
This code produces the following output:

2 squared = 4
3 squared = 9
4 squared = 16
*/

using System;

public class SamplesArray
{
    public static void Main()
    {
        // create a three element array of integers
        int[] intArray = new int[] {2, 3, 4};

        // set a delegate for the ShowSquares method
        Action<int> action = new Action<int>(ShowSquares);

        Array.ForEach(intArray, action);
    }

    private static void ShowSquares(int val)
    {
        Console.WriteLine("{0:d} squared = {1:d}", val, val*val);
    }
}

/*
This code produces the following output:

2 squared = 4
3 squared = 9
4 squared = 16
*/

open System

let showSquares val' =
    printfn $"%i{val'} squared = %i{val' * val'}"

// create a three element array of integers
let intArray = [| 2..4 |]

Array.ForEach(intArray, showSquares)
// Array.iter showSquares intArray

// This code produces the following output:
//     2 squared = 4
//     3 squared = 9
//     4 squared = 16

Public Class SamplesArray
    Public Shared Sub Main()
        ' create a three element array of integers
        Dim intArray() As Integer = New Integer() {2, 3, 4}

        ' set a delegate for the ShowSquares method
        Dim action As New Action(Of Integer)(AddressOf ShowSquares)

        Array.ForEach(intArray, action)
    End Sub

    Private Shared Sub ShowSquares(val As Integer)
        Console.WriteLine("{0:d} squared = {1:d}", val, val*val)
    End Sub
End Class

' This code produces the following output:
'
' 2 squared = 4
' 3 squared = 9
' 4 squared = 16

Remarks

The Action<T> is a delegate to a method that performs an action on the object passed to it. The elements of array are individually passed to the Action<T>.

This method is an O(n) operation, where n is the Length of array.

In F#, the Array.iter function can be used instead.

Applies to

See also