This menu gives a good idea of regular expressions. It is always good to specify the regular expression through edit and preview regular expression menu. Regular expression is very powerful tool but needs a detailed explanation to beginners. regular_expressionAttributes whose name match this expression will be selected.All attributes are present in the left list and can be shifted to the right list which is the list of selected attributes. attributesThe required attributes can be selected from this option.The attribute name can be selected from the drop down box of the parameter attribute if the meta data is known. attributeThe required attribute can be selected from this option.Please note that all nominal attributes are also selected irrespective of the given numerical condition. All numeric attributes whose examples all satisfy the mentioned numeric condition are selected. numeric_value_filter: When this option is selected another parameter (numeric condition) becomes visible in the Parameters panel.Attributes that have even a single missing value are not selected. no_missing_values: This option simply selects all the attributes of the ExampleSet which don't contain a missing value in any example.When this option is selected some other parameters (block type, use block type exception) become visible in the Parameters panel. For example value_series_start and value_series_end block types both belong to the value_series block type. It should be noted that block types may be hierarchical. This option allows selection of all the attributes of a particular block type. block_type: This option is similar in working to the value_type option.When this option is selected some other parameters (value type, use value type exception) become visible in the Parameters panel. The user should have a basic understanding of type hierarchy when selecting attributes through this option. For example real and integer types both belong to the numeric type. It should be noted that types are hierarchical. value_type: This option allows selection of all the attributes of a particular type.When this option is selected some other parameters (regular expression, use except expression) become visible in the Parameters panel. regular_expression: This option allows you to specify a regular expression for the attribute selection.(Since RapidMiner 6.0.4 the Operator will fail if a selected Attribute is not in the ExampleSet) When this option is selected another parameter becomes visible in the Parameters panel.

This option will not work if the meta data is not known. All attributes of ExampleSet are present in the list required attributes can be easily selected.

subset: This option allows selection of multiple attributes through a list.When this option is selected another parameter (attribute) becomes visible in the Parameters panel. single: This option allows selection of a single attribute.all: This option simply selects all the attributes of the ExampleSet.attribute_filter_typeThis parameter allows you to select the attribute selection filter the method you want to use for selecting attributes on which you want to apply mappings.This is usually used to reuse the same ExampleSet in further operators or to view the ExampleSet in the Results Workspace. The ExampleSet that was given as input is passed without changing to the output through this port. The ExampleSet with value mappings is output of this port. The Retrieve operator provides meta data along-with data. It is essential that meta data should be attached with the data for the input because attributes are specified in their meta data. The output of other operators can also be used as input. It is the output of the Retrieve operator in the attached Example Process. Please go through the parameters and the Example Process to develop a better understanding of this operator. Attribute values of selected attributes that match this regular expression are mapped by the specified value mapping. This operator allows you to specify a regular expression. This operator allows you to select attributes to make mappings in. Additionally, the operator allows defining a default mapping. Multiple mappings can be specified through the value mappings parameter. A single mapping can be specified using the parameters replace what and replace by as in Replace operator. But, one use of this operator can do mappings for attributes of only one type. replace the value 'green' by the value 'green_color') as well as numerical values (e.g. This operator can be used to replace nominal values (e.g. This operator can be applied on both numerical and nominal attributes. SynopsisThis operator maps specified values of selected attributes to new values.

Rapidmaps property map