c# - How to make array except

Array Except
The Array class provides methods for creating, manipulating, searching, and sorting arrays. The Array class is not part of the System.Collections namespaces. However, it is still considered a collection because it is based on the IList interface. An element is a value in an Array. The length of an Array is the total number of elements it can contain. The Array has a fixed capacity.

The following .net c# tutorial code demonstrates how we can get the difference between two Array instances. Here we will compare two Array instances and get only the elements from the first Array that do not exist in the second Array instance. In this .net c# example code, we will use Enumerable Except() method to get the difference between two Array instances.

The Enumerable Except() method produces the set difference of two sequences. This method exists in the System.Linq namespace. The set difference between the two sets is defined as the members of the first set that do not appear in the second set.

The Enumerable Except() method returns those elements in the first sequence that do not appear in the second sequence. It does not return those elements in the second sequence that do not appear in the first sequence. Only unique elements are returned.

The Enumerable Except(first, second) method’s first parameter is a sequence whose elements that are not also in the second sequence will be returned. The second parameter is a sequence whose elements that also occur in the first sequence will cause those elements to be removed from the returned sequence.

The Enumerable Except(first, second) method returns a sequence that contains the set difference of the elements of two sequences. This method throws ArgumentNullException if the first sequence or the second sequence is null.
array-except.aspx

<%@ Page Language="C#" AutoEventWireup="true"%>  
  
<!DOCTYPE html>  
<script runat="server">  
    protected void Button1_Click(object sender, System.EventArgs e)  
    {
        string[] colors = { "red", "pink", "violet", "white", "snow" };
        string[] morecolors = { "red", "maroon", "magenta", "white" };

        Label1.Text = "colors array.........<br />";
        foreach (string s in colors)
        {
            Label1.Text += s + "<br />";
        }

        Label1.Text += "<br />more colors array.........<br />";
        foreach (string s in morecolors)
        {
            Label1.Text += s + "<br />";
        }

        var exceptResult = colors.Except(morecolors);

        Label1.Text += "<br />after remove all color from colors array ";
        Label1.Text += "<br />which exists in more colors array...............<br />";
        foreach (string s in exceptResult)
        {
            Label1.Text += s + "<br />";
        }
    }  
</script>  
  
<html xmlns="http://www.w3.org/1999/xhtml">  
<head id="Head1" runat="server">  
    <title>c# example - array except</title>  
</head>  
<body>  
    <form id="form1" runat="server">  
    <div>  
        <h2 style="color:DarkBlue; font-style:italic;">  
            c# example - array except
        </h2>  
        <hr width="550" align="left" color="LightBlue" />    
  
        <asp:Label   
            ID="Label1"   
            runat="server"  
            Font-Size="Large"  
            >  
        </asp:Label>  
        <br />
        <asp:Button   
            ID="Button1"   
            runat="server"   
            Text="test array except"  
            OnClick="Button1_Click"
            Height="40"  
            Font-Bold="true"  
            />  
    </div>  
    </form>  
</body>  
</html>
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