public void Print(ID3 node, string result)
{
if (node.Parent == null)
{
result += "If " + node.Best;
}
if (node.Children == null || node.Children.Count == 0)
{
Console.WriteLine(result += ", THEN Play == " + node.Label + ".");
}
foreach (var child in node.Children)
{
var oldResult = result;
if (child.IsAttribute)
{
result += " AND " + child.Best;
}
if (child.IsValue)
{
result += " == " + child.Value;
}
Print(child, result);
result = oldResult;
}
}
public ID3(string val, ID3 parent, List <PieceOfData> data)
{
Value = val;
Parent = parent;
TrainData = data;
Children = new List <ID3>();
}
public void Split(List <PieceOfData> data, string target)
{
Best = GetBest(data, target);
var possibleValues = TrainData.Select(x => x.Attributes[GetIndex(Best)]).Distinct().ToArray();
ID3 parentNode = null;
if (Parent != null)
{
parentNode = new ID3(Best, this);
parentNode.Best = Best;
parentNode.IsAttribute = true;
parentNode.IsValue = false;
Children.Add(parentNode);
}
else
{
parentNode = this;
IsAttribute = true;
}
foreach (var v in possibleValues)
{
var child = new ID3(v, parentNode, TrainData);
child.IsValue = true;
child.IsAttribute = false;
parentNode.Children.Add(child);
child.Eval(data, target, Best);
}
return;
}
static void Main(string[] args)
{
#region DataTable
DataTable dataTable = new DataTable("PlayGolf");
dataTable.Columns.Add("Outlook");
dataTable.Columns.Add("Temperature");
dataTable.Columns.Add("Humidity");
dataTable.Columns.Add("Wind");
dataTable.Columns.Add("Play");
dataTable.Rows.Add("Sunny", "Hot", "High", "Weak", "No");
dataTable.Rows.Add("Sunny", "Hot", "High", "Strong", "No");
dataTable.Rows.Add("Overcast", "Hot", "High", "Weak", "Yes");
dataTable.Rows.Add("Rain", "Mild", "High", "Weak", "Yes");
dataTable.Rows.Add("Rain", "Cool", "Normal", "Weak", "Yes");
dataTable.Rows.Add("Rain", "Cool", "Normal", "Strong", "No");
dataTable.Rows.Add("Overcast", "Cool", "Normal", "Strong", "Yes");
dataTable.Rows.Add("Sunny", "Mild", "High", "Weak", "No");
dataTable.Rows.Add("Sunny", "Cool", "Normal", "Weak", "Yes");
dataTable.Rows.Add("Rain", "Mild", "Normal", "Weak", "Yes");
dataTable.Rows.Add("Sunny", "Mild", "Normal", "Strong", "Yes");
dataTable.Rows.Add("Overcast", "Mild", "High", "Strong", "Yes");
dataTable.Rows.Add("Overcast", "Hot", "Normal", "Weak", "Yes");
dataTable.Rows.Add("Rain", "Mild", "High", "Strong", "No");
#endregion
var data = new List <PieceOfData>();
var allData = new List <PieceOfData>();
int counter = 0;
string line;
string path = @"..\..\Data\data.txt";
// Read the file and display it line by line.
System.IO.StreamReader file =
new System.IO.StreamReader(path);
while ((line = file.ReadLine()) != null)
{
var split = line.Split(',');
var newData = new PieceOfData();
for (int i = 0; i < 5; i++)
{
newData.Attributes[i] = split[i];
}
newData.Outlook = split[0];
newData.Temperature = split[1];
newData.Humidity = split[2];
newData.Windy = split[3];
newData.Play = split[4];
data.Add(newData);
counter++;
}
var dTree = new ID3(data, "Play");
var result = "";
dTree.Print(dTree, result);
Console.ReadLine();
}
public ID3(string name, ID3 parent)
{
Name = name;
Parent = parent;
Children = new List <ID3>();
}