C# | Remove the first occurrence from the StringCollection

StringCollection class is a new addition to the .NET Framework class library that represents a collection of strings. StringCollection class is defined in the System.Collections.Specialized namespace.
StringCollection.Remove(String) method is used to remove the first occurrence of a specific string from the StringCollection.

Syntax:

public void Remove (string value);

Here, value is the string which is to be removed from the StringCollection. The value can be null.

Note:

• Duplicate strings are allowed in StringCollection.
• Only the first occurrence is removed. To remove all occurrences of the specified string, use RemoveAt(IndexOf(value)) repeatedly while IndexOf does not return -1.
• If the StringCollection does not contain the specified object, the StringCollection remains unchanged. No exception is thrown.
• This method performs a linear search; therefore, this method is an O(n) operation, where n is Count.

Example:

// C# code to remove the first
// occurrence of a specific string
// from the StringCollection
using System;
using System.Collections;
using System.Collections.Specialized;

class GFG {

    // Driver code
    public static void Main()
    {

        // creating a StringCollection named myCol
        StringCollection myCol = new StringCollection();

        // creating a string array named myArr
        String[] myArr = new String[] {"A", "A", "A", "B", "C",
                                           "C", "D", "D", "E"};

        // Copying the elements of a string
        // array to the end of the StringCollection.
        myCol.AddRange(myArr);

        Console.WriteLine("Elements in StringCollection are : ");

        // Displaying elements in StringCollection
        // named myCol
        foreach(Object obj in myCol)
            Console.WriteLine(obj);

        // Removing the first occurrence of
        // "A" from the StringCollection
        myCol.Remove("A");

        Console.WriteLine("Elements in StringCollection are : ");

        // Displaying elements in StringCollection
        // named myCol
        foreach(Object obj in myCol)
            Console.WriteLine(obj);

        // Removing the first occurrence of
        // "C" from the StringCollection
        myCol.Remove("C");

        Console.WriteLine("Elements in StringCollection are : ");

        // Displaying elements in StringCollection
        // named myCol
        foreach(Object obj in myCol)
            Console.WriteLine(obj);

        // Removing the first occurrence of
        // "A" from the StringCollection
        myCol.Remove("A");

        Console.WriteLine("Elements in StringCollection are : ");

        // Displaying elements in StringCollection
        // named myCol
        foreach(Object obj in myCol)
            Console.WriteLine(obj);

        // Removing the first occurrence of
        // "Z" from the StringCollection
        // It would not throw exception even
        // if "Z" does not exist in myCol
        myCol.Remove("Z");

        Console.WriteLine("Elements in StringCollection are : ");

        // Displaying elements in StringCollection
        // named myCol
        foreach(Object obj in myCol)
            Console.WriteLine(obj);
    }
}

Output:

Elements in StringCollection are : 
A
A
A
B
C
C
D
D
E
Elements in StringCollection are : 
A
A
B
C
C
D
D
E
Elements in StringCollection are : 
A
A
B
C
D
D
E
Elements in StringCollection are : 
A
B
C
D
D
E
Elements in StringCollection are : 
A
B
C
D
D
E

Reference:

• https://docs.microsoft.com/en-us/dotnet/api/system.collections.specialized.stringcollection.remove?view=netframework-4.7.2