Pivot.cs

using System;
using Waher.Script.Abstraction.Elements;
using Waher.Script.Model;
using Waher.Script.Objects;
using Waher.Script.Objects.Matrices;
 
namespace Waher.Script.Persistence.Functions
{
    public class Pivot : FunctionOneMatrixVariable
    {
        public Pivot(ScriptNode Argument, int Start, int Length, Expression Expression)
            : base(Argument, Start, Length, Expression)
        {
        }
 
        public override string FunctionName => nameof(Pivot);
 
        public override string[] DefaultArgumentNames => new string[] { "Object" };
 
        public override IElement EvaluateMatrix(IMatrix Argument, Variables Variables)
        {
            if (Argument is ObjectMatrix M && M.HasColumnNames)
            {
                int Rows = M.Columns - 1;
                int Columns = M.Rows + 1;
                string[] Names = new string[Columns];
                string[] Names0 = M.ColumnNames;
                IElement[,] Elements = new IElement[Rows, Columns];
                IElement[,] Elements0 = M.Values;
                int Column, Row;
 
                Names[0] = Names0[0];
                for (Column = 1; Column < Columns; Column++)
                    Names[Column] = Elements0[Column - 1, 0].AssociatedObjectValue?.ToString();
 
                for (Row = 0; Row < Rows; Row++)
                    Elements[Row, 0] = new StringValue(Names0[Row + 1]);
 
                for (Column = 1; Column < Columns; Column++)
                {
                    for (Row = 0; Row < Rows; Row++)
                        Elements[Row, Column] = Elements0[Column - 1, Row + 1];
                }
 
                return new ObjectMatrix(Elements)
                {
                    ColumnNames = Names
                };
            }
            else
                return Argument.Transpose();
        }
 
    }
}