Click or drag to resize
Accord.NET (logo)

Imputation Class

Imputation filter for filling missing values.
Inheritance Hierarchy
SystemObject
  Accord.Statistics.FiltersBaseFilterImputationTOptions, ImputationObject
    Accord.Statistics.FiltersImputationObject
      Accord.Statistics.FiltersImputation

Namespace:  Accord.Statistics.Filters
Assembly:  Accord.Statistics (in Accord.Statistics.dll) Version: 3.8.0
Syntax
[SerializableAttribute]
public class Imputation : Imputation<Object>
Request Example View Source

The Imputation type exposes the following members.

Constructors
Properties
  NameDescription
Public propertyActive
Gets or sets whether this filter is active. An inactive filter will repass the input table as output unchanged.
(Inherited from BaseFilterTOptions, TFilter.)
Public propertyColumns
Gets the collection of filter options.
(Inherited from BaseFilterTOptions, TFilter.)
Public propertyItemInt32
Gets options associated with a given variable (data column).
(Inherited from BaseFilterTOptions, TFilter.)
Public propertyItemString
Gets options associated with a given variable (data column).
(Inherited from BaseFilterTOptions, TFilter.)
Public propertyNumberOfInputs
Gets the number of inputs accepted by the model.
(Inherited from BaseFilterTOptions, TFilter.)
Public propertyNumberOfOutputs
Gets the number of outputs generated by the model.
(Inherited from ImputationT.)
Public propertyToken
Gets or sets a cancellation token that can be used to stop the learning algorithm while it is running.
(Inherited from BaseFilterTOptions, TFilter.)
Top
Methods
  NameDescription
Public methodAdd
Add a new column options definition to the collection.
(Inherited from BaseFilterTOptions, TFilter.)
Public methodApply(DataTable)
Applies the Filter to a DataTable.
(Inherited from BaseFilterTOptions, TFilter.)
Public methodApply(DataTable, String)
Applies the Filter to a DataTable.
(Inherited from BaseFilterTOptions, TFilter.)
Public methodDetect
Auto detects the filter options by analyzing a given DataTable.
(Inherited from ImputationT.)
Public methodEquals
Determines whether the specified object is equal to the current object.
(Inherited from Object.)
Protected methodFinalize
Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection.
(Inherited from Object.)
Public methodGetEnumerator
Returns an enumerator that iterates through the collection.
(Inherited from BaseFilterTOptions, TFilter.)
Public methodGetHashCode
Serves as the default hash function.
(Inherited from Object.)
Public methodGetType
Gets the Type of the current instance.
(Inherited from Object.)
Public methodLearn(DataTable, Double)
Learns a model that can map the given inputs to the desired outputs.
(Inherited from ImputationT.)
Public methodLearn(T, Double)
Learns a model that can map the given inputs to the desired outputs.
(Inherited from ImputationT.)
Protected methodMemberwiseClone
Creates a shallow copy of the current Object.
(Inherited from Object.)
Protected methodOnAddingOptions
Called when a new column options definition is being added. Can be used to validate or modify these options beforehand.
(Inherited from BaseFilterTOptions, TFilter.)
Protected methodProcessFilter
Processes the current filter.
(Inherited from ImputationT.)
Public methodToString
Returns a string that represents the current object.
(Inherited from Object.)
Public methodTransform(T)
Applies the transformation to an input, producing an associated output.
(Inherited from ImputationT.)
Public methodTransform(T)
Applies the transformation to a set of input vectors, producing an associated set of output vectors.
(Inherited from ImputationT.)
Public methodTransform(T, T)
Applies the transformation to a set of input vectors, producing an associated set of output vectors.
(Inherited from ImputationT.)
Top
Extension Methods
  NameDescription
Public Extension MethodHasMethod
Checks whether an object implements a method with the given name.
(Defined by ExtensionMethods.)
Public Extension MethodIsEqual
Compares two objects for equality, performing an elementwise comparison if the elements are vectors or matrices.
(Defined by Matrix.)
Public Extension MethodTo(Type)Overloaded.
Converts an object into another type, irrespective of whether the conversion can be done at compile time or not. This can be used to convert generic types to numeric types during runtime.
(Defined by ExtensionMethods.)
Public Extension MethodToTOverloaded.
Converts an object into another type, irrespective of whether the conversion can be done at compile time or not. This can be used to convert generic types to numeric types during runtime.
(Defined by ExtensionMethods.)
Top
Examples
// Suppose we have the following double data containing missing values 
// (indicated by Double.NaN values). Let's say we would like to replace 
// those NaN values by inputing likely values at their original locations:

double[][] data =
{
    new[] { Double.NaN,        0.5,  0.2,               0.7 },
    new[] {        1.2,        6.2,  1.2,               4.2 },
    new[] {         10,        2.2, -1.1,        Double.NaN },
    new[] {         10, Double.NaN, -1.1,               1.0 },
    new[] {         10,        2.2,  Double.NaN,        1.0 },
};

// Let's create a new data imputation filter:
var imputation = new Imputation<double>();

// Let's instruct it to replace NaN values in the first
// column by their median, values in the second column
// by their average, values in the third column by a fixed 
// value and values in the last column by their mode:
imputation[0].Strategy = ImputationStrategy.Median;
imputation[1].Strategy = ImputationStrategy.Mean;
imputation[2].Strategy = ImputationStrategy.FixedValue;
imputation[2].ReplaceWith = 42;
imputation[3].Strategy = ImputationStrategy.Mode;

// Learn from the data:
imputation.Learn(data);

// Now, let's transform the input data using the 
// data imputation rules we just defined above:
double[][] result = imputation.Transform(data);

// The result should be:
// 
//   double[][] expected = new double[][]
//   {
//       new[] {   a, 0.5,  0.2, 0.7 },
//       new[] { 1.2, 6.2,  1.2, 4.2 },
//       new[] {  10, 2.2, -1.1,   d },
//       new[] {  10,   b, -1.1, 1.0 },
//       new[] {  10, 2.2,    c, 1.0 },
//   };
See Also