How do I sum a list<> of arrays

Question

I have a List< int[] > myList, where I know that all the int[] arrays are the same length - for the sake of argument, let us say I have 500 arrays, each is 2048 elements long

Answer 1

Here is one that trades the Linq statement simplicity with performance.

var colSums = 
   from col in array.Pivot()
   select col.Sum();

---

 public static class LinqExtensions {
    public static IEnumerable<IEnumerable<T>> Pivot<T>( this IList<T[]> array ) {
        for( int c = 0; c < array[ 0 ].Length; c++ )
            yield return PivotColumn( array, c );
    }
    private static IEnumerable<T> PivotColumn<T>( IList<T[]> array, int c ) {
        for( int r = 0; r < array.Count; r++ )
            yield return array[ r ][ c ];
    }
}