How to Repeat String in C#

1. Repeat String With the String Class Constructor in C#
2. Repeat String With the LINQ Method in C#
3. Repeat String With the StringBuilder Class in C#

This tutorial will discuss the methods to repeat a string in C#.

Repeat String With the String Class Constructor in C#

The constructor of the String class can be used to repeat a specific string to a specified number of times in C#. The String class constructor takes two arguments, the character to be repeated and the number of times it should repeat. See the following code example.

using System;

namespace repeat_string {
  class Program {
    static void Main(string[] args) {
      string dimensions = new String('D', 3);
      Console.WriteLine(dimensions);
    }
  }
}

Output:

DDD

In the above code, we repeated the character D 3 times and saved it in the string variable dimensions with the String('D', 3) constructor in C#. This approach’s drawback is that we cannot repeat any strings; we can repeat a character. This drawback is addressed in the next section.

Repeat String With the LINQ Method in C#

The LINQ integrates query functionality with data structures in C#. The Enumerable.Repeat() function of LINQ can be used to repeat a string to a specified number of times in C#. The Enumerable.Repeat() function takes two parameters, a string variable and the number of times that string variable must be repeated. The following code example shows us how we can repeat a string with the Enumerable.Repeat() function of LINQ in C#.

using System;
using System.Linq;

namespace repeat_string {
  class Program {
    static void Main(string[] args) {
      string alphabets = string.Concat(Enumerable.Repeat("ABC", 3));
      Console.WriteLine(alphabets);
    }
  }
}

Output:

ABCABCABC

In the above code, we repeated the string ABC 3 times and saved it in the string variable alphabets with the Enumerable.Repeat("ABC", 3) function of LINQ in C#. This approach repeats strings instead of repeating characters like the previous approach.

Repeat String With the StringBuilder Class in C#

Another approach that can be used to repeat a string is to use the StringBuilder class in C#. The StringBuilder class is used to create a mutable string of characters in C#. See the following code example.

using System;
using System.Text;
namespace repeat_string {
  class Program {
    static void Main(string[] args) {
      string alphabets = new StringBuilder("ABC".Length * 3).Insert(0, "ABC", 3).ToString();
      Console.WriteLine(alphabets);
    }
  }
}

Output:

ABCABCABC

In the above code, we repeated the string ABC 3 times and stored it in the string variable alphabets with the StringBuilder class and StringBuilder.Insert() function in C#. First, we created a new string with the combined length of the repeated string with the StringBuilder("ABC".Length*3) constructor. It created a string of length 9 because the length of ABC is 3, and it must be repeated 3 times. Then, we start from the index 0 and insert the string ABC 3 times into the newly created string with the Insert() function. In the end, we convert the resultant value to a string with the ToString() function in C#. This approach is not recommended because it does the same job as the previous approach but is more complex.