Collection<T>.Contains(T) method is used to determine whether an element is in the Collection<T>.
Syntax:
public bool Contains (T item);
Here, item is the object to locate in the Collection<T>. The value can be null for reference types.
Return Value: This method return True if item is found in the Collection<T>, otherwise, False.
Below given are some examples to understand the implementation in a better way:
Example 1:
// C# code to check if an // element is in 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 >();
myColl.Add( "A" );
myColl.Add( "B" );
myColl.Add( "C" );
myColl.Add( "D" );
myColl.Add( "E" );
// Checking if an element is in the Collection
// The function returns "True" if the
// item is present in Collection
// else returns "False"
Console.WriteLine(myColl.Contains( "A" ));
}
} |
Output:
True
Example 2:
// C# code to check if an // element is in 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 >();
myColl.Add(2);
myColl.Add(3);
myColl.Add(4);
myColl.Add(5);
// Checking if an element is in the Collection
// The function returns "True" if the
// item is present in Collection
// else returns "False"
Console.WriteLine(myColl.Contains(6));
}
} |
Output:
False
Note: This method performs a linear search. Therefore, this method is an O(n) operation, where n is Count.
Reference: