C# Program to convert integer array to string array

Converting an integer array to a string array is a common task in C# programming. The most efficient approach is using the Array.ConvertAll() method, which applies a conversion function to each element in the source array and returns a new array of the target type.

Syntax

Following is the syntax for Array.ConvertAll() method −

string[] result = Array.ConvertAll(sourceArray, converter);

Parameters

• sourceArray − The source integer array to convert

• converter − A lambda expression or method that converts each element

Return Value

Returns a new string array containing the converted elements from the source array.

Using Array.ConvertAll() with Lambda Expression

The most common approach uses a lambda expression to convert each integer to its string representation −

using System;

public class Demo {
   public static void Main() {
      int[] intArray = new int[5];
      
      // Initialize integer array with 5 elements
      intArray[0] = 15;
      intArray[1] = 30;
      intArray[2] = 44;
      intArray[3] = 50;
      intArray[4] = 66;
      
      // Convert integer array to string array
      string[] strArray = Array.ConvertAll(intArray, ele => ele.ToString());
      
      Console.WriteLine("Original integer array: [" + string.Join(", ", intArray) + "]");
      Console.WriteLine("Converted string array: [" + string.Join(", ", strArray) + "]");
   }
}

The output of the above code is −

Original integer array: [15, 30, 44, 50, 66]
Converted string array: [15, 30, 44, 50, 66]

Using Array.ConvertAll() with Method Group

You can also use method group syntax for cleaner code −

using System;

public class Demo {
   public static void Main() {
      int[] numbers = {10, 20, 30, 40, 50};
      
      // Convert using method group syntax
      string[] stringNumbers = Array.ConvertAll(numbers, Convert.ToString);
      
      Console.WriteLine("Using Convert.ToString method:");
      foreach (string str in stringNumbers) {
         Console.WriteLine("'" + str + "' (Type: " + str.GetType().Name + ")");
      }
   }
}

The output of the above code is −

Using Convert.ToString method:
'10' (Type: String)
'20' (Type: String)
'30' (Type: String)
'40' (Type: String)
'50' (Type: String)

Using LINQ Select Method

An alternative approach uses LINQ's Select() method combined with ToArray() −

using System;
using System.Linq;

public class Demo {
   public static void Main() {
      int[] intArray = {100, 200, 300, 400, 500};
      
      // Convert using LINQ Select
      string[] strArray = intArray.Select(x => x.ToString()).ToArray();
      
      Console.WriteLine("Using LINQ Select:");
      Console.WriteLine("[" + string.Join(" | ", strArray) + "]");
      
      // Verify the type conversion
      Console.WriteLine("First element type: " + strArray[0].GetType().Name);
   }
}

The output of the above code is −

Using LINQ Select:
[100 | 200 | 300 | 400 | 500]
First element type: String

Comparison

Conclusion

The Array.ConvertAll() method is the most efficient way to convert an integer array to a string array in C#. It provides excellent performance and requires no additional dependencies. For functional programming enthusiasts, LINQ's Select().ToArray() offers a more expressive alternative with minimal performance overhead.