How to find the length of jagged array using a property?

A jagged array in C# is an array of arrays where each inner array can have different lengths. To find the length of a jagged array, you use the Length property, which returns the number of inner arrays (rows) in the jagged array.

Syntax

Following is the syntax for declaring a jagged array −

dataType[][] arrayName = new dataType[size][];

To get the length of a jagged array, use the Length property −

int numberOfRows = arrayName.Length;

Using Length Property

The Length property returns the number of rows (outer arrays) in the jagged array −

using System;

public class Program {
   public static void Main() {
      int[][] arr = new int[][] {
         new int[] {0, 0},
         new int[] {1, 2},
         new int[] {2, 4},
         new int[] {3, 6},
         new int[] {4, 8}
      };
      
      Console.WriteLine("Number of rows: " + arr.Length);
      Console.WriteLine("Length of first row: " + arr[0].Length);
      Console.WriteLine("Length of second row: " + arr[1].Length);
   }
}

The output of the above code is −

Number of rows: 5
Length of first row: 2
Length of second row: 2

Jagged Array with Different Row Lengths

Here's an example showing a jagged array where each row has different lengths −

using System;

public class Program {
   public static void Main() {
      int[][] jaggedArray = new int[][] {
         new int[] {1},
         new int[] {2, 3},
         new int[] {4, 5, 6},
         new int[] {7, 8, 9, 10}
      };
      
      Console.WriteLine("Total rows: " + jaggedArray.Length);
      
      for (int i = 0; i < jaggedArray.Length; i++) {
         Console.WriteLine("Row " + i + " length: " + jaggedArray[i].Length);
         Console.Write("Elements: ");
         for (int j = 0; j < jaggedArray[i].Length; j++) {
            Console.Write(jaggedArray[i][j] + " ");
         }
         Console.WriteLine();
      }
   }
}

The output of the above code is −

Total rows: 4
Row 0 length: 1
Elements: 1 
Row 1 length: 2
Elements: 2 3 
Row 2 length: 3
Elements: 4 5 6 
Row 3 length: 4
Elements: 7 8 9 10 

Additional Array Properties

Besides Length, jagged arrays support other useful properties and methods −

using System;

public class Program {
   public static void Main() {
      int[][] arr = new int[][] {
         new int[] {0, 0},
         new int[] {1, 2},
         new int[] {2, 4},
         new int[] {3, 6},
         new int[] {4, 8}
      };
      
      Console.WriteLine("Length: " + arr.Length);
      Console.WriteLine("Upper Bound: " + arr.GetUpperBound(0));
      Console.WriteLine("Lower Bound: " + arr.GetLowerBound(0));
      Console.WriteLine("Dimensions of Array: " + arr.Rank);
   }
}

The output of the above code is −

Length: 5
Upper Bound: 4
Lower Bound: 0
Dimensions of Array: 1

Conclusion

The Length property of a jagged array returns the number of rows (outer arrays) it contains. Each individual row can have its own length, which you can access using arrayName[index].Length. This flexibility makes jagged arrays useful when you need arrays of varying sizes.