private string[] GetGroupedAttributePossibleValues(PropertyInfo prop, NominalAttribute att, string[] attvals)
{
var togroup = GetAttributeValuesToGroup(att, attvals);
Array.ForEach(data, row => {
var val = InternalHelpers.ToStringSafe(Helpers.GetValue(row, prop.Name));
var idx = Array.BinarySearch(togroup, val);
while (idx >= 0)
{
Helpers.SetValue(row, prop.Name, "Others");
idx = idx == togroup.Length ? -1 : Array.BinarySearch(togroup, idx + 1, togroup.Length - (idx + 1), val);
}
});
return(attvals.Concat(new[] { "Others" }).Distinct().Except(togroup).ToArray());
}
private static string[] GetAttributeValuesToGroup(NominalAttribute att, string[] atts)
{
if (att is NominalGroupWhenLessThanAttribute)
{
var min = ((NominalGroupWhenLessThanAttribute)att).Min;
return(atts.GroupBy(a => a).
Where(g => g.Count() < min).
Select(g => g.Key).
OrderBy(a => a).
ToArray());
}
if (att is NominalGroupMaxBinsAttribute)
{
var max = ((NominalGroupMaxBinsAttribute)att).Max;
return(atts.GroupBy(a => a).
OrderByDescending(g => g.Count()).
Skip(max).
Select(g => g.Key).
OrderBy(a => a).ToArray());
}
throw new NotSupportedException("Type: " + att.GetType().Name + " does not support grouping");
}
