Swapping Characters of a String in C#

To swap characters of a string, use the Select method.

Firstly, let’s say our string is −

string str = "PQRQP";

Now, you need to swap every occurrence of P with Q and Q with P −

str.Select(a=> a == 'P' ? 'Q' : (a=='Q' ? 'P' : a)).ToArray();

The above replaces the characters.

Let us see the compelet code −

Example

using System;
using System.Linq;

public class Program {
   public static void Main() {

      string str = "PQRQP";

      var res= str.Select(a=> a == 'P' ? 'Q' : (a=='Q' ? 'P' : a)).ToArray();
      str = new String(res);

      Console.WriteLine(str);
   }
}

Output

QPRPQ