public void ValueMapOneValueTest()
{
var data = new[] { new TestClass()
{
A = "bar", B = "test", C = "foo"
} };
var dataView = ML.Data.LoadFromEnumerable(data);
var keys = new List <string>()
{
"foo", "bar", "test", "wahoo"
};
var values = new List <int>()
{
1, 2, 3, 4
};
var lookupMap = DataViewHelper.CreateDataView(Env, keys, values,
ValueMappingTransformer.DefaultKeyColumnName,
ValueMappingTransformer.DefaultValueColumnName, false);
var estimator = new ValueMappingEstimator <string, int>(Env, lookupMap,
lookupMap.Schema[ValueMappingTransformer.DefaultKeyColumnName],
lookupMap.Schema[ValueMappingTransformer.DefaultValueColumnName],
new[] { ("D", "A"), ("E", "B"), ("F", "C") });
/// <summary>
/// Create a <see cref="ValueMappingEstimator"/>, which converts value types into keys, loading the keys to use from <paramref name="keyValuePairs"/>.
/// </summary>
/// <typeparam name="TInputType">The key type.</typeparam>
/// <typeparam name="TOutputType">The value type.</typeparam>
/// <param name="catalog">The conversion transform's catalog</param>
/// <param name="outputColumnName">Name of the column resulting from the transformation of <paramref name="inputColumnName"/>.
/// The output data types can be primitives or vectors of numeric, text, boolean, <see cref="System.DateTime"/>, <see cref="System.DateTimeOffset"/> or <see cref="DataViewRowId"/> types.</param>
/// <param name="keyValuePairs">Specifies the mapping that will be performed. The keys will be mapped to the values as specified in the <paramref name="keyValuePairs"/>.</param>
/// <param name="inputColumnName">Name of the column to transform.
/// If set to <see langword="null"/>, the value of the <paramref name="outputColumnName"/> will be used as source.
/// The input data types can be primitives or vectors of numeric, text, boolean, <see cref="System.DateTime"/>, <see cref="System.DateTimeOffset"/> or <see cref="DataViewRowId"/> types.
/// </param>
/// <param name="treatValuesAsKeyType">Whether to treat the values as a key.</param>
/// <returns>An instance of the <see cref="ValueMappingEstimator"/></returns>
/// <example>
/// <format type="text/markdown">
/// <]
/// ]]></format>
/// </example>
public static ValueMappingEstimator <TInputType, TOutputType> MapValue <TInputType, TOutputType>(
this TransformsCatalog.ConversionTransforms catalog,
string outputColumnName,
IEnumerable <KeyValuePair <TInputType, TOutputType> > keyValuePairs,
string inputColumnName = null,
bool treatValuesAsKeyType = false)
{
var keys = keyValuePairs.Select(pair => pair.Key);
var values = keyValuePairs.Select(pair => pair.Value);
var lookupMap = DataViewHelper.CreateDataView(catalog.GetEnvironment(), keys, values,
ValueMappingTransformer.DefaultKeyColumnName,
ValueMappingTransformer.DefaultValueColumnName, treatValuesAsKeyType);
return(new ValueMappingEstimator <TInputType, TOutputType>(catalog.GetEnvironment(), lookupMap,
lookupMap.Schema[ValueMappingTransformer.DefaultKeyColumnName],
lookupMap.Schema[ValueMappingTransformer.DefaultValueColumnName],
new[] { (outputColumnName, inputColumnName ?? outputColumnName) }));