How to copy part of an array to another array in C#?

int[] b = new int[3];
Array.Copy(a, 1, b, 0, 3);

• a = source array
• 1 = start index in source array
• b = destination array
• 0 = start index in destination array
• 3 = elements to copy

See this question. LINQ Take() and Skip() are the most popular answers, as well as Array.CopyTo().

A purportedly faster extension method is described here.

In case if you want to implement your own Array.Copy method.

Static method which is of generic type.

 static void MyCopy<T>(T[] sourceArray, long sourceIndex, T[] destinationArray, long destinationIndex, long copyNoOfElements)
 {
  long totaltraversal = sourceIndex + copyNoOfElements;
  long sourceArrayLength = sourceArray.Length;

  //to check all array's length and its indices properties before copying
  CheckBoundaries(sourceArray, sourceIndex, destinationArray, copyNoOfElements, sourceArrayLength);
   for (long i = sourceIndex; i < totaltraversal; i++)
     {
      destinationArray[destinationIndex++] = sourceArray[i]; 
     } 
  }

Boundary method implementation.

private static void CheckBoundaries<T>(T[] sourceArray, long sourceIndex, T[] destinationArray, long copyNoOfElements, long sourceArrayLength)
        {
            if (sourceIndex >= sourceArray.Length)
            {
                throw new IndexOutOfRangeException();
            }
            if (copyNoOfElements > sourceArrayLength)
            {
                throw new IndexOutOfRangeException();
            }
            if (destinationArray.Length < copyNoOfElements)
            {
                throw new IndexOutOfRangeException();
            }
        }

In C# 8+ you can use ranges.

int a[] = {1,2,3,4,5};
int b[] = a[1..4]; // b = [2,3,4];

https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/proposals/csharp-8.0/ranges