using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace String1
{
class Program
{
static void Main(string[] args)
{
Console.WriteLine("Enter Your String.");
string myString = Console.ReadLine();
var onlyLetters = new String(myString.Where(Char.IsLetter).ToArray());
Console.WriteLine(onlyLetters);
Console.Read();
}
}
}
Here, the Final Output is shown in the following image. Here output is According to our Input String as Uppercase and Lowercase.
![Final Output]()
If we want only Print Uppercase(Capital Letter) only that time we change in condition Char.IsUpper (c)).ToArray().
class Program
{
static void Main(string[] args)
{
Console.WriteLine("Enter Your String.");
string myString = Console.ReadLine();
var onlyLetters = new String(myString.Where(c => Char.IsLetter(c) && Char.IsUpper(c)).ToArray());
Console.WriteLine(onlyLetters);
Console.Read();
}
}
The final output is shown in the following image.
![String Output]()
3-You can achieve this using Regex.Replace. Firstly add a namespace using System.Text.RegularExpressions.
class Program
{
static void Main(string[] args)
{
Console.WriteLine("Enter Your String.");
string myString = Console.ReadLine();
// var onlyLetters = new String(myString.Where(Char.IsLetter).ToArray());
string newmysring = Regex.Replace(myString, "[^a-zA-Z]", "");
Console.WriteLine(newmysring);
Console.Read();
}
}
Here Final Output is shown in the following image.
![Here Final Output]()
4- C# program that prints alternative letters of a given string.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;
namespace String1
{
class Program
{
static void Main(string[] args)
{
Console.WriteLine("Enter Your String.");
string myString = Console.ReadLine();
string alternativeLetters = "";
for (int i = 0; i < myString.Length; i += 2)
{
alternativeLetters += myString[i];
}
Console.WriteLine(alternativeLetters);
Console.Read();
}
}
}
Here Final Output is shown in the following image.
![LINQ]()
Alternatively, you can use LINQ to achieve the same result in a more concise way.
class Program
{
static void Main(string[] args)
{
Console.WriteLine("Enter Your String.");
string myString = Console.ReadLine();
string alternativeLetters = new string(myString.Where((c, i) => i % 2 == 0).ToArray());
Console.WriteLine(alternativeLetters);
Console.Read();
}
}
The final output is shown in the following image.
![LINQ expression]()
This LINQ expression uses the `Where` method to select characters at even indices (0, 2, 4, ...) and then converts the resulting sequence back to a string.