This transformer can be used to ensure that the representation of null, empty, and missing attributes on the feature matches the representation expected by the output format, or downstream transformer.
In addition, some users might use a special value to represent null, missing, or empty. This transformer will allow you to map to and from that special value.
Attributes To Map
Whether to map All Attributes or Selected Attributes. All Attributes will operate on all attributes present on the feature, including format attributes. Please note that All Attributes will not operate on missing attributes. To map missing attributes, users must choose Selected Attributes.
Users must explicitly specify attributes to be mapped. Please note that checking ‘Select all’ within the ‘Select Selected Attributes Items’ dialog is not generally the same as choosing All Attributes for the Map parameter. For example, many existing attributes on the feature may not be exposed. In this case, All Attributes will process these unexposed attributes, while Selected Attributes will not be able to.
For the specified attributes, check the value of the attribute in the input feature and if it is one of the specified values, take the action specified by the Map To parameter. Values that can be matched are:
- Empty – The attribute exists and has an empty string as its value.
- Null – The attribute exists and has a value of null.
- Missing (Selected Attributes Only) – The attribute does not exist.
If this parameter has a value and the attribute value matches the specified value, the Map To action will be applied.
If this parameter has a value and the attribute value contains the specified regular expression, then the Map To action will be applied. The containment check is case-sensitive. Advanced regular expression (AREs) are supported. If the attribute value matches the specified regular expression, then the Map To action will be applied.
This table lists the special characters:
||||separates "branches" (or choices)|
|*||a sequence of 0 or more matches of what precedes it|
|+||a sequence of 1 or more matches of what precedes it|
|?||a sequence of 0 or 1 matches of what precedes it|
|.||matches any single character|
|^||matches the start of the value|
|$||matches the end of the value|
|[ ]||enclose a set of character choices|
|( )||enclose a "subexpression"|
|a||any character can be listed to be matched|
This parameter specifies how to map matching attributes. Possible actions are:
- Null – This will cause the attribute to be set to a null value.
- Missing – The attribute will be deleted.
- Empty String – The attribute value will be set to an empty string (which has length 0).
- New Value – The attribute will be set to the value specified by the New Value parameter.
This parameter specifies the value to set an attribute to if New Value is specified as the Map To action.
Editing Transformer Parameters
Using a set of menu options, transformer parameters can be assigned by referencing other elements in the workspace. More advanced functions, such as an advanced editor and an arithmetic editor, are also available in some transformers. To access a menu of these options, click beside the applicable parameter. For more information, see Transformer Parameter Menu Options.
Associated FME function or factory: @Tcl2
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Tags Keywords: NullAttributeReplacer NullAttributeRemover BulkAttributeMapper