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Rename by Replacing

Synopsis​

This operator can be used to rename a set of attributes by replacing parts of the attribute names by a specified replacement.

Description​

The Rename by Replacing operator replaces parts of the attribute names by the specified replacement. This operator is used mostly for removing unwanted parts of attribute names like whitespaces, parentheses, or other unwanted characters. The replace what parameter defines that part of the attribute name that should be replaced. It can be defined as a regular expression which 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. The replace by parameter can be defined as an arbitrary string. Empty strings are also allowed. Capturing groups of the regular expression of the replace what parameter can be accessed with $1, $2, $3 etc. Please study the attached Example Process for more understanding.

Please keep in mind that attribute names must be unique. The Rename by Replacing operator has no impact on the type or role of an attribute. For example if you have an attribute named 'alpha' of integer type and regular role. Renaming the attribute to 'beta' will just change its name. It will retain its type integer and role regular. To change the role of an operator, use the <reference key="operator.set_role">Set Role</reference> operator. Many type conversion operators are available for changing the type of an attribute at 'Data Transformation/Type Conversion'.

Input​

example set input​

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. It is essential that meta data should be attached with the data for the input because attributes are specified in their meta data.

Output​

example set output​

The ExampleSet with renamed attributes is output of this port.

original​

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 type​

This 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.

Attribute​

The required attribute 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.

Attributes​

The required attributes can be selected from this option. This opens a new window with two lists. All attributes are present in the left list and can be shifted to the right list, which is the list of selected attributes.

Regular expression​

The 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.

Use except expression​

If 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.

Except regular expression​

This 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).

Value type​

The type of attributes to be selected can be chosen from a drop down list.

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.

Except value type​

The attributes matching this type will not be selected even if they match the previously mentioned type i.e. value type parameter's value.

Block type​

The block type of attributes to be selected can be chosen from a drop down list.

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.

Except block type​

The 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.

Numeric condition​

The 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.

Include special attributes​

The 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.

Invert selection​

If 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.

Replace what​

The replace what parameter defines that part of the attribute name that should be replaced. It can be defined as a regular expression. Capturing groups of the regular expression of the replace what parameter can be accessed in the replace by parameter with $1, $2, $3 etc.

Replace by​

The replace by parameter can be defined as an arbitrary string. Empty strings are also allowed. Capturing groups of the regular expression of the replace what parameter can be accessed with $1, $2, $3 etc.