C# Array ForEach Action
In this chapter you will learn:
- Array.ForEach with a delegate
- Example for Array ForEach Action
- ForEach with your own delegate
- Use an Action to change the values
Description
You can enumerate using the static Array.ForEach method:
public static void ForEach<T> (T[] array, Action<T> action);
This uses an Action delegate, with this signature:
public delegate void Action<T> (T obj);Example
Example for Array ForEach Action
using System;//from www .jav a2 s . co m
public class MainClass{
public static void Main(){
int[] array = new int[] { 8, 2, 3, 5, 1, 3 };
Array.ForEach<int>(array, delegate(int x) { Console.Write(x + " "); });
Console.WriteLine();
}
}
The code above generates the following result.
We can further rewrite the code above as below.
using System;//from w ww. ja v a 2s .c om
using System.Collections;
class Sample
{
public static void Main()
{
Array.ForEach(new[] { 1, 2, 3 }, Console.WriteLine);
}
}
The output:
ForEach with your own delegate
using System;
/* ww w .j av a 2 s .c o m*/
class MyClass {
public int i;
public MyClass(int x) {
i = x;
}
}
class MainClass {
static void show(MyClass o) {
Console.Write(o.i + " ");
}
public static void Main() {
MyClass[] nums = new MyClass[5];
nums[0] = new MyClass(5);
nums[1] = new MyClass(2);
nums[2] = new MyClass(3);
nums[3] = new MyClass(4);
nums[4] = new MyClass(1);
Console.Write("Contents of nums: ");
// Use action to show the values.
Array.ForEach(nums, MainClass.show);
Console.WriteLine();
}
}
The code above generates the following result.
Change array element in a ForEach Action
using System;
/* w ww . ja v a2 s . c o m*/
class MyClass {
public int i;
public MyClass(int x) {
i = x;
}
}
class MainClass {
static void neg(MyClass o) {
o.i = -o.i;
}
static void show(MyClass o) {
Console.Write(o.i + " ");
}
public static void Main() {
MyClass[] nums = new MyClass[5];
nums[0] = new MyClass(5);
nums[1] = new MyClass(2);
nums[2] = new MyClass(3);
nums[3] = new MyClass(4);
nums[4] = new MyClass(1);
// Use action to negate the values.
Array.ForEach(nums, MainClass.neg);
// Use action to show the values.
Array.ForEach(nums, MainClass.show);
}
}
The code above generates the following result.
Next chapter...
What you will learn in the next chapter: