FME Transformers: 2024.2

Categories
Attributes

Attributes

Categories
Attributes

Attributes

ListRenamer

Renames or promotes list names or components. When promoting or renaming, if the resulting name collides with an existing attribute name, the existing attribute will be overwritten.

For the discussion below the following terms are introduced:

  • Component – This is a piece of an attribute name. For example, in list{}.blat{}.foo, there are 3 components. Two components are lists: list{} and blat{}. One component is not a list: foo.
  • Subcomponent – This is a component of a list. Thus, in list{}.blat{}.foo, blat{} is a subcomponent of list{}. Similarly, foo is a subcomponent of blat{}.
  • Structured List – a list for which a subcomponent contains more than one piece of data. The elements of the structure are represented as foo{}.a or foo{}.b.

Examples

Example 1

If the List to Process is somelist{} and the incoming feature contains:

somelist{0}.length = 7.3

somelist{2}.length = 5

somelist{3}.height = 6

If somelist{} is renamed to anotherName{}, the result will be:

anotherName{0}.length = 7.3

anotherName{2}.length = 5

anotherName{3}.height = 6

Example 2

If the List to Process is somelist{}.listTwo{}, the List Action is Promote – listTwo{1}, and the incoming feature contains:

somelist{0}.listTwo{0} = 0

somelist{0}.listTwo{1} = 1

somelist{0}.listTwo{3} = 2

Then the result will be:

somelist{0}.listTwo = 1

Example 3

If the List to Process is somelist{}.listTwo{}, the List Action is Promote – listTwo{1} and the incoming feature contains:

somelist{0}.listTwo{0}.length = 0

somelist{0}.listTwo{1}.length = 1

somelist{0}.listTwo{1}.height{0} = 3

somelist{0}.listTwo{3}.length = 2

Then the result will be:

somelist{0}.length = 1

somelist{0}.height{0} = 3

Example 4

If the List to Process is somelist{}, the List Action is Promote All Subcomponents and incoming feature contains the following:

somelist{0}.length = 7.3

somelist{2}.length = 5

somelist{3}.height = 6

The result will be:

length{0} = 7.3

length{2} = 5

height{3} = 6

Configuration

Parameters

List to Process

The selected list and list components that will be renamed or promoted. Selecting a list will cause the table to populate with the components available for renaming.

Changing the List to Process will cause the List Action to switch to Rename.

List Action

The action to perform on the list.

  • Rename means the components in the selected name will be renamed only. The components of the selected list will be listed in the ‘List Component Name’ column of the List Components To Rename table. The ‘New Name’ will default to the old one.

  • Promote means the last component of the List to Process will be promoted. It will no longer be a subcomponent of the list but a ‘sibling component’.

    If the last component is not a list, that item will become a list at the same level as its parent list.

    If the last component of the List To Process is a list, then the user will be prompted to select a list index to promote. When promoting a specific element within a list, the behavior will depend on whether the list is structured (ie. List{}.bar{}.a). If it is structured, then the subcomponents will become subcomponents of the parent. If the list is unstructured (ie. List{}.bar{}.foo{}), then the list name will become a component at the same level as the parent list (ie. List{}.foo).

    If this option is selected, the List Components to Rename will be populated with the components of the List to Process up until the last component.

  • Promote All Subcomponents means that all subcomponents of the selected list will be promoted. This option is only available if none of the subcomponents are lists. Each subcomponent will become a list at the same level as the parent list.

    If this option is selected, the List Components to Rename will give the list of the subcomponents of the List to Process.

When promoting list components, the promoted components will receive the index of their parent. As a result, if the incoming list has gaps, the outgoing list will also have gaps.

Keep Original List

Whether or not to delete the original list entry when renaming. If set to Yes then renaming will create a new attribute with the desired name and the original entry will still remain. If set to No then the attribute will be renamed.

When promoting a specific element in a list, if Keep Original List is set to No, all list elements that do not match the specified element to promote will be removed.

This table will be populated appropriately when the user selects a List to Process and List Action. For each component, the ‘New Name’ column specifies the desired name for the component.

To rename a component, type the desired component name in the ‘New Name’ column for that component. Then at runtime, the transformer will rename the components to the desired component names.

Additional Resources

More Information on Lists

Editing Transformer Parameters

Transformer parameters can be set by directly entering values, using expressions, or referencing other elements in the workspace such as attribute values or user parameters. Various editors and context menus are available to assist. To see what is available, click beside the applicable parameter.

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.

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.

Text Editor

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.

Arithmetic Editor

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.

String Functions

These functions manipulate and format strings.

Special Characters

 A set of control characters is available in the Text Editor.

Math Functions

Math functions are available in both editors.
Date/Time Functions Date and time functions are available in the Text Editor.

Math Operators

These operators are available in the Arithmetic Editor.

FME Feature Functions

These return primarily feature-specific values.

FME Parameters

FME and workspace-specific parameters may be used.
Creating and Modifying User Parameters Create your own editable parameters.

Table Tools

Transformers with table-style parameters have additional tools for populating and manipulating values.

Row Reordering

Enabled once you have clicked on a row item. Choices include:

  • Add a row
  • Remove a row
  • Move current row up one
  • Move current row down one
  • Move current row to top
  • Move current row to bottom

Cut, Copy, and Paste

Enabled once you have clicked on a row item. Choices include:

  • Cut a row - delete and copy to clipboard
  • Copy a row to the clipboard
  • Paste a row from the clipboard

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.

For more information, see Transformer Parameter Menu Options.

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