Synopsis
Maps all values to real values (usually simply using the internal indices).
Description
This operator maps all non numeric attributes to real valued attributes. Nothing is done for numeric attributes, binary attributes are mapped to 0 and 1. For nominal attributes one of the following calculations will be done:
- Dichotomization, i.e. one new attribute for each value of the nominal attribute. The new attribute which corresponds to the actual nominal value gets value 1 and all other attributes gets value 0.
- Alternatively the values of nominal attributes can be seen as equally ranked, therefore the nominal attribute will simply be turned into a real valued attribute, the old values results in equidistant real values.
At this moment the same applies for ordinal attributes, in a future release more appropriate values based on the ranking between the ordinal values may be included.
Input
- example set input: expects: ExampleSetMetaData: #examples: = 0; #attributes: 0
, Example set matching at least one selected attribute.
Output
- example set output:
- original:
- preprocessing model:
Parameters
- return preprocessing model: Indicates if the preprocessing model should also be returned
- create view: Create View to apply preprocessing instead of changing the data
- attribute filter type: The condition specifies which attributes are selected or affected by this operator.
- attribute: The attribute which should be chosen.
- attributes: The attribute which should be chosen.
- regular expression: A regular expression for the names of the attributes which should be kept.
- use except expression: If enabled, an exception to the specified regular expression might be specified. Attributes of matching this will be filtered out, although matching the first expression.
- except regular expression: A regular expression for the names of the attributes which should be filtered out although matching the above regular expression.
- value type: The value type of the attributes.
- use value type exception: If enabled, an exception to the specified value type might be specified. Attributes of this type will be filtered out, although matching the first specified type.
- except value type: Except this value type.
- block type: The block type of the attributes.
- use block type exception: If enabled, an exception to the specified block type might be specified.
- except block type: Except this block type.
- numeric condition: Parameter string for the condition, e.g. '>= 5'
- invert selection: Indicates if only attributes should be accepted which would normally filtered.
- include special attributes: Indicate if this operator should also be applied on the special attributes. Otherwise they are always kept.