Combining Result Sets

Question

I am trying to create a list of all possible product / value combinations for each product in the catalog. Each product can have a variable number of options, and each parameter can have a variable number of values.

So, for example, I had a shirt, and the parameter / values ​​were color (red, yellow, blue), size (s, m, l) and material (cotton, nylon, blend). I want to create a list that looks like this:

red, s, cotton
red, s, nylon
red, s, blend
red, m, cotton
red, m, nylon
red, m, blend
red, l, cotton
red, l, nylon
red, l, blend
yellow, s, cotton
yellow, s, nylon
yellow, s, blend
yellow, m, cotton
yellow, m, nylon
yellow, m, blend
yellow, l, cotton
yellow, l, nylon
yellow, l, blend
blue, s, cotton
blue, s, nylon
blue, s, blend
blue, m, cotton
blue, m, nylon
blue, m, blend
blue, l, cotton
blue, l, nylon
blue, l, blend

I know that theoretically this can lead to a large number of results, but in practice most products have only two or three options with two or three values ​​each.

I work in C #, but any code sample would be very helpful. Thanks so much for any suggestions!

Answer 1

:

public class Color
{
    private readonly string _color;

    public Color(string color)
    {
        _color = color;
    }

    public override string ToString()
    {
        return _color;
    }
}

public class Size
{
    private readonly string _size;

    public Size(string size)
    {
        _size = size;
    }

    public override string ToString()
    {
        return _size;
    }
}

public class Material
{
    private readonly string _material;

    public Material(string material)
    {
        _material = material;
    }

    public override string ToString()
    {
        return _material;
    }
}

:

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            var colors = new List<Color>() { new Color("Red"), 
                                             new Color("Yellow"), 
                                             new Color("Blue") };

            var sizes = new List<Size>() { new Size("S"), 
                                           new Size("M"), 
                                           new Size("L") };

            var materials = new List<Material>() { new Material("Cotton"),
                                                   new Material("Nylon"),
                                                   new Material("Blend") };

            var products = from c in colors
                           from s in sizes
                           from m in materials
                           select new { Color = c, Size = s, Material = m };


            foreach (var p in products)
            {
                Console.WriteLine("{0}, {1}, {2}", p.Color, p.Size, p.Material);
            }
            Console.ReadKey(true);
        }
    }
}

Answer 2

var results =   from c in colours
                from s in sizes
                from m in materials
                select Tuple.Create(c, s, m);

:

select new { Colour = c, Size = s, Material = m };

Answer 3

It could be that simple:

public class Product
{
  public string Colour { get; set; }
  public string Size { get; set; }
  public string Material { get; set; }
}

IList<Product> products = new List<Product>();
foreach (string colour in colours)
{
  foreach (string size in sizes)
  {
    foreach (string material in materials)
    {
      products.Add(new Product 
      {
        Colour = colour,
        Size = size,
        Material = material
      });
    }
  }
}

Where colours, sizesand materialsare string arrays of values. Is that what you expected?

Answer 4

This is actually a cross join, not a concatenation.

You can do this quite simply in C # using LINQ or nested foreach loops. The LINQ method is pretty straightforward. Assuming colors, sizes and fabrics already exist as collections in your code.

from color in colors
from size in sizes
from fabric in fabrics
select new {
    color,
    size,
    fabric
}

Answer 5

Also consider:

public enum Color    {Red, Yellow, Blue};
public enum Size     {S, M, L};
public enum Material {Cotton, Nylon, Blend};
public class Product
{
   public Color    color;
   public Size     size;
   public Material material;
}

List<Product> products = new List<Product>();

int numColors    = Enum.GetValues(typeof(Color)).Length;
int numSizes     = Enum.GetValues(typeof(Size)).Length;
int numMaterials = Enum.GetValues(typeof(Material)).Length;

for(int i = 0; i < numColors; i++)
   for(int j = 0; k < numSizes; j++)
       for(int k = 0; k < numMaterials; k++)
       {
          Product p  = new Product();
          p.color    = (Color)i;
          p.size     = (Size)j;
          p.material = (Material)k;
          products.Add(p);
       }