public static ColumnInferenceResults InferColumns(MLContext context, string path, ColumnInformation columnInfo, bool hasHeader,
TextFileContents.ColumnSplitResult splitInference, ColumnTypeInference.InferenceResult typeInference,
bool trimWhitespace, bool groupColumns)
{
var loaderColumns = ColumnTypeInference.GenerateLoaderColumns(typeInference.Columns);
var typedLoaderOptions = new TextLoader.Options
{
Columns = loaderColumns,
Separators = new[] { splitInference.Separator.Value },
AllowSparse = splitInference.AllowSparse,
AllowQuoting = splitInference.AllowQuote,
ReadMultilines = splitInference.ReadMultilines,
HasHeader = hasHeader,
TrimWhitespace = trimWhitespace
};
var textLoader = context.Data.CreateTextLoader(typedLoaderOptions);
var dataView = textLoader.Load(path);
// Validate all columns specified in column info exist in inferred data view
ColumnInferenceValidationUtil.ValidateSpecifiedColumnsExist(columnInfo, dataView);
var purposeInferenceResult = PurposeInference.InferPurposes(context, dataView, columnInfo);
// start building result objects
IEnumerable <TextLoader.Column> columnResults = null;
IEnumerable <(string, ColumnPurpose)> purposeResults = null;
// infer column grouping and generate column names
if (groupColumns)
{
var groupingResult = ColumnGroupingInference.InferGroupingAndNames(context, hasHeader,
typeInference.Columns, purposeInferenceResult);
columnResults = groupingResult.Select(c => c.GenerateTextLoaderColumn());
purposeResults = groupingResult.Select(c => (c.SuggestedName, c.Purpose));
}
else
{
columnResults = loaderColumns;
purposeResults = purposeInferenceResult.Select(p => (dataView.Schema[p.ColumnIndex].Name, p.Purpose));
}
var textLoaderOptions = new TextLoader.Options()
{
Columns = columnResults.ToArray(),
AllowQuoting = splitInference.AllowQuote,
AllowSparse = splitInference.AllowSparse,
Separators = new char[] { splitInference.Separator.Value },
ReadMultilines = splitInference.ReadMultilines,
HasHeader = hasHeader,
TrimWhitespace = trimWhitespace
};
return(new ColumnInferenceResults()
{
TextLoaderOptions = textLoaderOptions,
ColumnInformation = ColumnInformationUtil.BuildColumnInfo(purposeResults)
});
}
private static ColumnTypeInference.InferenceResult InferColumnTypes(MLContext context, TextFileSample sample,
TextFileContents.ColumnSplitResult splitInference, bool hasHeader, uint?labelColumnIndex, string label)
{
// infer column types
var typeInferenceResult = ColumnTypeInference.InferTextFileColumnTypes(context, sample,
new ColumnTypeInference.Arguments
{
ColumnCount = splitInference.ColumnCount,
Separator = splitInference.Separator.Value,
AllowSparse = splitInference.AllowSparse,
AllowQuote = splitInference.AllowQuote,
HasHeader = hasHeader,
LabelColumnIndex = labelColumnIndex,
Label = label
});
if (!typeInferenceResult.IsSuccess)
{
throw new InferenceException(InferenceExceptionType.ColumnDataType, "Unable to infer column types of the file provided.");
}
return(typeInferenceResult);
}