public static StreamingDataView <TRow> CreateFromEnumerable <TRow>(IHostEnvironment env, IEnumerable <TRow> data,
SchemaDefinition schemaDefinition = null)
where TRow : class
{
Contracts.AssertValue(env);
env.AssertValue(data);
env.AssertValueOrNull(schemaDefinition);
var internalSchemaDefn = schemaDefinition == null
? InternalSchemaDefinition.Create(typeof(TRow), SchemaDefinition.Direction.Read)
: InternalSchemaDefinition.Create(typeof(TRow), schemaDefinition);
return(new StreamingDataView <TRow>(env, data, internalSchemaDefn));
}
public static IDataView CreateFromList <TRow>(IHostEnvironment env, IList <TRow> data,
SchemaDefinition schemaDefinition = null)
where TRow : class
{
Contracts.AssertValue(env);
env.AssertValue(data);
env.AssertValueOrNull(schemaDefinition);
var internalSchemaDefn = schemaDefinition == null
? InternalSchemaDefinition.Create(typeof(TRow))
: InternalSchemaDefinition.Create(typeof(TRow), schemaDefinition);
return(new ListDataView <TRow>(env, data, internalSchemaDefn));
}
public static ISchemaBoundMapper CreateBound <T>(IHostEnvironment env, ISchemaBoundRowMapper mapper, VectorType type, Delegate getter,
string metadataKind, Func <ISchemaBoundMapper, ColumnType, bool> canWrap)
{
Contracts.AssertValue(env);
env.AssertValue(mapper);
env.AssertValue(type);
env.AssertValue(getter);
env.Assert(getter is ValueGetter <VBuffer <T> >);
env.AssertNonEmpty(metadataKind);
env.AssertValueOrNull(canWrap);
return(new Bound <T>(env, mapper, type, (ValueGetter <VBuffer <T> >)getter, metadataKind, canWrap));
}
/// <summary>
/// Create a Cursorable object on a given data view.
/// </summary>
/// <param name="env">Host environment.</param>
/// <param name="data">The underlying data view.</param>
/// <param name="ignoreMissingColumns">Whether to ignore missing columns in the data view.</param>
/// <param name="schemaDefinition">The optional user-provided schema.</param>
/// <returns>The constructed Cursorable.</returns>
public static TypedCursorable <TRow> Create(IHostEnvironment env, IDataView data, bool ignoreMissingColumns, SchemaDefinition schemaDefinition)
{
Contracts.AssertValue(env);
env.AssertValue(data);
env.AssertValueOrNull(schemaDefinition);
ValidateUserType(schemaDefinition, typeof(TRow), data);
var outSchema = schemaDefinition == null
? InternalSchemaDefinition.Create(typeof(TRow), SchemaDefinition.Direction.Write)
: InternalSchemaDefinition.Create(typeof(TRow), schemaDefinition);
return(new TypedCursorable <TRow>(env, data, ignoreMissingColumns, outSchema));
}
private void SaveInputSchema(DataViewSchema inputSchema, RepositoryWriter rep)
{
_env.AssertValueOrNull(inputSchema);
_env.AssertValue(rep);
if (inputSchema == null)
{
return;
}
using (var ch = _env.Start("Saving Schema"))
{
var entry = rep.CreateEntry(SchemaEntryName);
var saver = new BinarySaver(_env, new BinarySaver.Arguments {
Silent = true
});
DataSaverUtils.SaveDataView(ch, saver, new EmptyDataView(_env, inputSchema), entry.Stream, keepHidden: true);
}
}