Guess Types (RapidMiner Studio Core)

Synopsis

This operator (re-)guesses the value types of all attributes of the input ExampleSet and changes them accordingly.

Description

The Guess Types operator can be used to (re-)guess the value types of the attributes of the input ExampleSet. This might be useful after some preprocessing transformations and purification of some of the attributes. This operator can be useful especially if nominal attributes can be handled as numerical attributes after some preprocessing. It is not necessary to (re-)guess the type of all the attributes with this operator. You can select the attributes whose type is to be (re-)guessed. Please study the attached Example Process for more information. Please note that this operator has no impact on the values of the ExampleSet.

Input

  • example set input (Data Table)

    This input port expects an ExampleSet. It is the output of the Retrieve operator in the attached Example Process. The output of other operators can also be used as input.

Output

  • example set output (Data Table)

    The type of the selected attributes of the input ExampleSet is (re-)guessed and the resultant ExampleSet is delivered through this output port.

  • original (Data Table)

    The ExampleSet that was given as input is passed without changing to the output through this port. This is usually used to reuse the same ExampleSet in further operators or to view the ExampleSet in the Results Workspace.

Parameters

  • attribute_filter_typeThis parameter allows you to select the attribute selection filter; the method you want to use for selecting attributes. It has the following options:
    • all: This option simply selects all the attributes of the ExampleSet This is the default option.
    • single: This option allows selection of a single attribute. When this option is selected another parameter (attribute) becomes visible in the Parameters panel.
    • subset: This option allows selection of multiple attributes through a list. All attributes of ExampleSet are present in the list; required attributes can be easily selected. This option will not work if meta data is not known. When this option is selected another parameter becomes visible in the Parameters panel.
    • regular_expression: This option allows you to specify a regular expression for attribute selection. When this option is selected some other parameters (regular expression, use except expression) become visible in the Parameters panel.
    • value_type: This option allows selection of all the attributes of a particular type. It should be noted that types are hierarchical. For example real and integer types both belong to the numeric type. Users should have basic understanding of type hierarchy when selecting attributes through this option. When this option is selected some other parameters (value type, use value type exception) become visible in the Parameters panel.
    • block_type: This option is similar in working to the value_type option. This option allows selection of all the attributes of a particular block type. It should be noted that block types may be hierarchical. For example value_series_start and value_series_end block types both belong to the value_series block type. When this option is selected some other parameters (block type, use block type exception) become visible in the Parameters panel.
    • no_missing_values: This option simply selects all the attributes of the ExampleSet which don't contain a missing value in any example. Attributes that have even a single missing value are removed.
    • numeric value filter: When this option is selected another parameter (numeric condition) becomes visible in the Parameters panel. All numeric attributes whose examples all satisfy the mentioned numeric condition are selected. Please note that all nominal attributes are also selected irrespective of the given numerical condition.
    Range: selection
  • attributeThe required attribute can be selected from this option. The attribute name can be selected from the drop down box of parameter attribute if the meta data is known. Range: string
  • attributesThe required attributes can be selected from this option. This opens a new window with two lists. All attributes are present in the left list. Attributes can be shifted to the right list, which is the list of selected attributes. Range: string
  • regular_expressionThe attributes whose name match this expression will be selected. Regular expression is a very powerful tool but needs a detailed explanation to beginners. It is always good to specify the regular expression through the edit and preview regular expression menu. This menu gives a good idea of regular expressions and it also allows you to try different expressions and preview the results simultaneously. Range: string
  • use_except_expressionIf enabled, an exception to the first regular expression can be specified. When this option is selected another parameter (except regular expression) becomes visible in the Parameters panel. Range: boolean
  • except_regular_expressionThis option allows you to specify a regular expression. Attributes matching this expression will be filtered out even if they match the first regular expression (regular expression that was specified in the regular expression parameter). Range: string
  • value_typeThe type of attributes to be selected can be chosen from a drop down list. Range: selection
  • use_value_type_exception If enabled, an exception to the selected type can be specified. When this option is enabled, another parameter (except value type) becomes visible in the Parameters panel. Range: boolean
  • except_value_typeThe attributes matching this type will not be selected even if they match the previously mentioned type i.e. value type parameter's value. Range: selection
  • block_typeThe block type of attributes to be selected can be chosen from a drop down list. Range: selection
  • use_block_type_exception If enabled, an exception to the selected block type can be specified. When this option is selected another parameter (except block type) becomes visible in the Parameters panel. Range: boolean
  • except_block_typeThe attributes matching this block type will be not be selected even if they match the previously mentioned block type i.e. block type parameter's value. Range: selection
  • numeric_conditionThe numeric condition for testing examples of numeric attributes is specified here. For example the numeric condition '> 6' will keep all nominal attributes and all numeric attributes having a value of greater than 6 in every example. A combination of conditions is possible: '> 6 && < 11' or '<= 5 || < 0'. But && and || cannot be used together in one numeric condition. Conditions like '(> 0 && < 2) || (>10 && < 12)' are not allowed because they use both && and ||. Use a blank space after '>', '=' and '<' e.g. '<5' will not work, so use '< 5' instead. Range: string
  • include_special_attributesThe special attributes are attributes with special roles which identify the examples. In contrast regular attributes simply describe the examples. Special attributes are: id, label, prediction, cluster, weight and batch. By default all special attributes are selected irrespective of the conditions in the Select Attribute operator. If this parameter is set to true, Special attributes are also tested against conditions specified in the Select Attribute operator and only those attributes are selected that satisfy the conditions. Range: boolean
  • invert_selectionIf this parameter is set to true, it acts as a NOT gate, it reverses the selection. In that case all the selected attributes are unselected and previously unselected attributes are selected. For example if attribute 'att1' is selected and attribute 'att2' is unselected prior to checking of this parameter. After checking of this parameter 'att1' will be unselected and 'att2' will be selected. Range: boolean
  • first_character_indexThis parameter specifies the index of the first character of the substring which should be kept. Please note that the counting starts with 1. Range: integer
  • last_character_indexThis parameter specifies the index of the last character of the substring which should be kept. Please note that the counting starts with 1. Range: integer
  • decimal_point_characterThe character specified by this parameter is used as the decimal character. Range: char
  • number_grouping_characterThe character specified by this parameter is used as the grouping character. This character is used for grouping the numbers. If this character is found between numbers, the numbers are combined and this character is ignored. For example if "22-14" is present in the ExampleSet and "-" is set as the number grouping character, then the number will be considered to be "2214". Range: char

Tutorial Processes

Guessing the type of an attribute after preprocessing

The 'Iris' data set is loaded using the Retrieve operator. A breakpoint is inserted here so that you can have a look at the ExampleSet. Please note the 'id' attribute. The 'id' attribute is of nominal type and it has the values of the format 'id_1', 'id_2' and so on. The Cut operator is applied on the ExampleSet to remove the substring 'id_' from the start of the 'id' attribute values. A breakpoint is inserted after the Cut operator. You can see that now the values in the 'id' attribute are of the form '1', '2', '3' and so on but the type of this attribute is still nominal. The Guess Types operator is applied on this ExampleSet. The attribute filter type parameter is set to 'single', the attribute parameter is set to 'id' and the include special attributes parameter is also set to 'true'. Thus the Guess Types operator will re-guess the type of the 'id' attribute. A breakpoint is inserted after the Guess Type operator. You can see that the type of the 'id' attribute has now been changed to integer.