C# | Removing first occurrence of object from Collection<T>
Last Updated :
01 Feb, 2019
Collection<T>.Remove(T) is used to remove the first occurrence of a specific object from the Collection<
T>.
Syntax:
public bool Remove (T item);
Here,
item is the object to remove from the Collection<
T>. The value can be null for reference types.
Return Value: True if item is successfully removed, otherwise,
False. This method also returns
False if item was not found in the original Collection<
T>.
Below given are some examples to understand the implementation in a better way:
Example 1:
CSHARP
// C# code to remove the first
// occurrence of a specific object
// from the Collection
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
class GFG {
// Driver code
public static void Main()
{
// Creating a collection of strings
Collection<string> myColl = new Collection<string>();
// Adding elements in Collection myColl
myColl.Add("A");
myColl.Add("B");
myColl.Add("C");
myColl.Add("D");
myColl.Add("E");
// Displaying the number of elements in myColl
Console.WriteLine("Count : " + myColl.Count);
// Displaying the elements in myColl
foreach(string str in myColl)
{
Console.WriteLine(str);
}
// Removing the first occurrence of
// a specific object from the Collection
myColl.Remove("C");
// Displaying the number of elements in myColl
Console.WriteLine("Count : " + myColl.Count);
// Displaying the elements in myColl
foreach(string str in myColl)
{
Console.WriteLine(str);
}
}
}
Output:
Count : 5
A
B
C
D
E
Count : 4
A
B
D
E
Example 2:
CSHARP
// C# code to remove the first
// occurrence of a specific object
// from the Collection
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
class GFG {
// Driver code
public static void Main()
{
// Creating a collection of ints
Collection<int> myColl = new Collection<int>();
// Adding elements in Collection myColl
myColl.Add(2);
myColl.Add(3);
myColl.Add(4);
myColl.Add(4);
myColl.Add(5);
// Displaying the number of elements in myColl
Console.WriteLine("Count : " + myColl.Count);
// Displaying the elements in myColl
foreach(int i in myColl)
{
Console.WriteLine(i);
}
// Removing the first occurrence of
// a specific object from the Collection
myColl.Remove(4);
// Displaying the number of elements in myColl
Console.WriteLine("Count : " + myColl.Count);
// Displaying the elements in myColl
foreach(int i in myColl)
{
Console.WriteLine(i);
}
}
}
Output:
Count : 5
2
3
4
4
5
Count : 4
2
3
4
5
Note: This method performs a linear search. Therefore this method is an
O(n) operation, where n is Count.
Reference: