Removes all duplicate values from a list attribute. In the resulting list, only distinct values for the list attribute will be present.
When looking for duplicates, null, missing and empty values are considered equivalent so will be treated as duplicates of each other. The first null, missing or empty string value will be kept.
If there were other attributes in the list “parallel” to the attribute being operated on, these will also be moved in the list to stay in “parallel” with the key attribute. Similarly, if there were other attributes in the list “parallel” to an entry that is a duplicate (so will be removed), those attributes will also be removed.
For matching purposes, a list entry is considered ‘missing’, only if it has a parallel attribute. For example, if list{0}.a exists, then list{0}.b will be considered missing. However if there are no list{0} entries, then list{0}.b will not be considered missing. It rather will be considered to represent a ‘gap’ in the list.
Example
If this feature enters this transformer:
somelist{0}.kind = 'paved'
somelist{1}.kind = 'smooth'
somelist{2}.kind = 'smooth'
somelist{3}.kind = 'rough'
somelist{4}.kind = 'smooth'
somelist{5}.kind = 'smooth'
somelist{6}.kind = 'paved'
somelist{8}.kind = <Null>
and the list name is set to somelist{}.kind, the feature leaving the transformer will have these attributes:
somelist{0}.kind = 'paved'
somelist{1}.kind = 'smooth'
somelist{2}.kind = 'rough'
somelist{3}.kind = <Null>
As another example, if the input feature had these attributes:
somelist{0}.kind = 'paved'
somelist{0}.id = 'A3'
somelist{1}.kind = 'smooth'
somelist{1}.id = 'B7'
somelist{2}.kind = 'smooth'
somelist{2}.id = 'B8'
somelist{3}.kind = 'rough'
somelist{3}.id = 'C9'
somelist{4}.kind = 'smooth'
somelist{4}.id = 'B9'
somelist{5}.kind = 'smooth'
somelist{5}.id = 'B2'
somelist{6}.kind = 'paved'
somelist{6}.id = 'A7'
and the list name is set to somelist{}.kind, the feature leaving the transformer will have these attributes:
somelist{0}.kind = 'paved'
somelist{0}.id = 'A3'
somelist{1}.kind = 'smooth'
somelist{1}.id = 'B7'
somelist{2}.kind = 'rough'
somelist{2}.id = 'C9'
Configuration
Parameters
General
|
List Attribute |
Specifies the list attribute from which to remove duplicates. |
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.
Defining Values
There are several ways to define a value for use in a Transformer. The simplest is to simply type in a value or string, which can include functions of various types such as attribute references, math and string functions, and workspace parameters. There are a number of tools and shortcuts that can assist in constructing values, generally available from the drop-down context menu adjacent to the value field.
How to Set Parameter Values
Using the Text Editor
The Text Editor provides a convenient way to construct text strings (including regular expressions) from various data sources, such as attributes, parameters, and constants, where the result is used directly inside a parameter.
Using the Arithmetic Editor
The Arithmetic Editor provides a convenient way to construct math expressions from various data sources, such as attributes, parameters, and feature functions, where the result is used directly inside a parameter.
Conditional Values
Set values depending on one or more test conditions that either pass or fail.
Parameter Condition Definition Dialog
Content
Expressions and strings can include a number of functions, characters, parameters, and more.
When setting values - whether entered directly in a parameter or constructed using one of the editors - strings and expressions containing String, Math, Date/Time or FME Feature Functions will have those functions evaluated. Therefore, the names of these functions (in the form @<function_name>) should not be used as literal string values.
Content Types
| These functions manipulate and format strings. | |
|
Special Characters |
A set of control characters is available in the Text Editor. |
| Math functions are available in both editors. | |
| Date/Time Functions | Date and time functions are available in the Text Editor. |
| These operators are available in the Arithmetic Editor. | |
| These return primarily feature-specific values. | |
| FME and workspace-specific parameters may be used. | |
| Creating and Modifying User Parameters | Create your own editable parameters. |
Dialog Options - Tables
Transformers with table-style parameters have additional tools for populating and manipulating values.
Table Tools
|
Row Reordering
|
Enabled once you have clicked on a row item. Choices include:
|
|
Cut, Copy, and Paste
|
Enabled once you have clicked on a row item. Choices include:
Cut, copy, and paste may be used within a transformer, or between transformers. |
|
Filter
|
Start typing a string, and the matrix will only display rows matching those characters. Searches all columns. This only affects the display of attributes within the transformer - it does not alter which attributes are output. |
|
Import
|
Import populates the table with a set of new attributes read from a dataset. Specific application varies between transformers. |
|
Reset/Refresh
|
Generally resets the table to its initial state, and may provide additional options to remove invalid entries. Behavior varies between transformers. |
Note: Not all tools are available in all transformers.
FME Community
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