/// <summary>
/// Auto-detect purpose for the data view columns.
/// </summary>
public static PurposeInference.Column[] InferPurposes(MLContext context, IDataView data,
ColumnInformation columnInfo)
{
data = context.Data.TakeRows(data, MaxRowsToRead);
var allColumns = new List <IntermediateColumn>();
var columnsToInfer = new List <IntermediateColumn>();
for (var i = 0; i < data.Schema.Count; i++)
{
var column = data.Schema[i];
IntermediateColumn intermediateCol;
if (column.IsHidden)
{
intermediateCol = new IntermediateColumn(data, i, ColumnPurpose.Ignore);
allColumns.Add(intermediateCol);
continue;
}
var columnPurpose = columnInfo.GetColumnPurpose(column.Name);
if (columnPurpose == null)
{
intermediateCol = new IntermediateColumn(data, i);
columnsToInfer.Add(intermediateCol);
}
else
{
intermediateCol = new IntermediateColumn(data, i, columnPurpose.Value);
}
allColumns.Add(intermediateCol);
}
foreach (var expert in GetExperts())
{
expert.Apply(columnsToInfer.ToArray());
}
return(allColumns.Select(c => c.GetColumn()).ToArray());
}
