public void CategoricalOneHotEncodingFromSideData()
{
// In this case, whatever the value of the input, the term mapping should come from the optional side data if specified.
var data = new[] { new TestStringClass()
{
A = "Stay"
}, new TestStringClass()
{
A = "awhile and listen"
} };
var mlContext = new MLContext();
var dataView = mlContext.Data.ReadFromEnumerable(data);
var sideDataBuilder = new ArrayDataViewBuilder(mlContext);
sideDataBuilder.AddColumn("Hello", "hello", "my", "friend");
var sideData = sideDataBuilder.GetDataView();
var ci = new OneHotEncodingEstimator.ColumnInfo("CatA", "A", OneHotEncodingTransformer.OutputKind.Bag);
var pipe = mlContext.Transforms.Categorical.OneHotEncoding(new[] { ci }, sideData);
var output = pipe.Fit(dataView).Transform(dataView);
VBuffer <ReadOnlyMemory <char> > slotNames = default;
output.Schema["CatA"].GetSlotNames(ref slotNames);
Assert.Equal(3, slotNames.Length);
Assert.Equal("hello", slotNames.GetItemOrDefault(0).ToString());
Assert.Equal("my", slotNames.GetItemOrDefault(1).ToString());
Assert.Equal("friend", slotNames.GetItemOrDefault(2).ToString());
Done();
}
public override IEstimator <ITransformer> Reconcile(IHostEnvironment env, PipelineColumn[] toOutput,
IReadOnlyDictionary <PipelineColumn, string> inputNames, IReadOnlyDictionary <PipelineColumn, string> outputNames, IReadOnlyCollection <string> usedNames)
{
var infos = new OneHotEncodingEstimator.ColumnInfo[toOutput.Length];
Action <ValueToKeyMappingTransformer> onFit = null;
for (int i = 0; i < toOutput.Length; ++i)
{
var tcol = (ICategoricalCol)toOutput[i];
infos[i] = new OneHotEncodingEstimator.ColumnInfo(inputNames[tcol.Input], outputNames[toOutput[i]], (OneHotEncodingTransformer.OutputKind)tcol.Config.OutputKind,
tcol.Config.Max, (ValueToKeyMappingTransformer.SortOrder)tcol.Config.Order);
if (tcol.Config.OnFit != null)
{
int ii = i; // Necessary because if we capture i that will change to toOutput.Length on call.
onFit += tt => tcol.Config.OnFit(tt.GetTermMap(ii));
}
}
var est = new OneHotEncodingEstimator(env, infos);
if (onFit != null)
{
est.WrapTermWithDelegate(onFit);
}
return(est);
}
