Property names generated in AutoML's GenerateSampleData() differ from those generated by GenerateClassLabels()

[mstfbl]

As @LittleLittleCloud noted in this comment in PR #5177 for fixing Issue #3902, columns generated from inline data are currently named in the following way:

machinelearning/src/Microsoft.ML.CodeGenerator/Utils.cs

Lines 49 to 68 in 33f5f32

	internal static IDictionary<string, string> GenerateSampleData(IDataView dataView, ColumnInferenceResults columnInference)
	{
	var featureColumns = dataView.Schema.AsEnumerable().Where(col => col.Name != columnInference.ColumnInformation.LabelColumnName && !columnInference.ColumnInformation.IgnoredColumnNames.Contains(col.Name));
	var rowCursor = dataView.GetRowCursor(featureColumns);
	var sampleData = featureColumns.Select(column => new { key = Utils.Normalize(column.Name), val = "null" }).ToDictionary(x => x.key, x => x.val);
	if (rowCursor.MoveNext())
	{
	var getGetGetterMethod = typeof(Utils).GetMethod(nameof(Utils.GetValueFromColumn), BindingFlags.Static | BindingFlags.Public | BindingFlags.NonPublic);
	foreach (var column in featureColumns)
	{
	var getGeneraicGetGetterMethod = getGetGetterMethod.MakeGenericMethod(column.Type.RawType);
	string val = getGeneraicGetGetterMethod.Invoke(null, new object[] { rowCursor, column }) as string;
	sampleData[Utils.Normalize(column.Name)] = val;
	}
	}
	return sampleData;
	}

This method of directly using Utils.Normalize is different from using GenerateClassLabels instead to obtain normalized and sanitized column names. GenerateClassLabels can accommodate conflicting/duplicate column names, whereas in GenerateSampleData() this situation results in exceptions.

machinelearning/src/Microsoft.ML.CodeGenerator/Utils.cs

Lines 246 to 318 in 33f5f32

	internal static IList<string> GenerateClassLabels(ColumnInferenceResults columnInferenceResults, IDictionary<string, CodeGeneratorSettings.ColumnMapping> columnMapping = default)
	{
	IList<string> result = new List<string>();
	foreach (var column in columnInferenceResults.TextLoaderOptions.Columns)
	{
	StringBuilder sb = new StringBuilder();
	int range = (column.Source[0].Max - column.Source[0].Min).Value;
	bool isArray = range > 0;
	sb.Append(Symbols.PublicSymbol);
	sb.Append(Symbols.Space);
	// if column is in columnMapping, use the type and name in that
	DataKind dataKind;
	string columnName;
	if (columnMapping != null && columnMapping.ContainsKey(column.Name))
	{
	dataKind = columnMapping[column.Name].ColumnType;
	columnName = columnMapping[column.Name].ColumnName;
	}
	else
	{
	dataKind = column.DataKind;
	columnName = column.Name;
	}
	switch (dataKind)
	{
	case Microsoft.ML.Data.DataKind.String:
	sb.Append(Symbols.StringSymbol);
	break;
	case Microsoft.ML.Data.DataKind.Boolean:
	sb.Append(Symbols.BoolSymbol);
	break;
	case Microsoft.ML.Data.DataKind.Single:
	sb.Append(Symbols.FloatSymbol);
	break;
	case Microsoft.ML.Data.DataKind.Double:
	sb.Append(Symbols.DoubleSymbol);
	break;
	case Microsoft.ML.Data.DataKind.Int32:
	sb.Append(Symbols.IntSymbol);
	break;
	case Microsoft.ML.Data.DataKind.UInt32:
	sb.Append(Symbols.UIntSymbol);
	break;
	case Microsoft.ML.Data.DataKind.Int64:
	sb.Append(Symbols.LongSymbol);
	break;
	case Microsoft.ML.Data.DataKind.UInt64:
	sb.Append(Symbols.UlongSymbol);
	break;
	default:
	throw new ArgumentException($"The data type '{column.DataKind}' is not handled currently.");
	}
	if (range > 0)
	{
	result.Add($"[ColumnName(\"{columnName}\"),LoadColumn({column.Source[0].Min}, {column.Source[0].Max}) VectorType({(range + 1)})]");
	sb.Append("[]");
	}
	else
	{
	result.Add($"[ColumnName(\"{columnName}\"), LoadColumn({column.Source[0].Min})]");
	}
	sb.Append(" ");
	sb.Append(Utils.Normalize(column.Name));
	sb.Append("{get; set;}");
	result.Add(sb.ToString());
	result.Add("\r\n");
	}
	return result;
	}

To-do:

• Ensure GenerateSampleData() can accomodate conflicting/duplicate column names by using Utils.GenerateClassLabels().