Count with string operator

   
 

using System;
using System.Linq;
using System.Collections;
using System.Collections.Generic;

public class MainClass {
    public static void Main() {
        string[] presidents = {"G", "H", "a", "H", "over", "Jack"};

        int count = presidents.Count(s => s.StartsWith("H"));
        Console.WriteLine(count);

    }
}

    


Count with string value

   
 

using System;
using System.Linq;
using System.Collections;
using System.Collections.Generic;

public class MainClass {
    public static void Main() {
        string[] presidents = {"G", "H", "a", "H", "over", "Jack"};
        int count = presidents.Count();
        Console.WriteLine(count);
    }
}

    


Contains with IEqualityComparer

   
 

using System;
using System.Linq;
using System.Collections;
using System.Collections.Generic;
public class MyStringifiedNumberComparer : IEqualityComparer<string> {
    public bool Equals(string x, string y) {
        return (Int32.Parse(x) == Int32.Parse(y));
    }

    public int GetHashCode(string obj) {
        return Int32.Parse(obj).ToString().GetHashCode();
    }
}
public class MainClass {
    public static void Main() {
        string[] stringifiedNums = {"001", "49", "017", "0080", "00027", "2" };
        bool contains = stringifiedNums.Contains("2",new MyStringifiedNumberComparer());
        Console.WriteLine(contains);
    }
}

    


Use Contains to check the existance of an element

   
 
using System;
using System.Collections;
using System.Collections.Generic;
using System.Text;
using System.Linq;

public class MainClass{
   public static void Main(){
       int[] numbers = { 2, 6, 1, 56, 102 };
       Console.WriteLine("Is there the number 102?");
       Console.Write(numbers.Contains(102) ? "Yes, there is" : "No, there isn&#039;t");
   }
}