AttributeFilter

Routes features to different output ports depending on the value of an attribute. The set of possible attribute values can be entered manually, or extracted from an input source in the properties dialog.

Jump to Configuration

Typical Uses

Separating features based on attribute values for further individual processing
Extracting one or more groups of features from a dataset based on attribute values
Selecting features from a dataset that match specific values and discarding the rest
Grooming a dataset by keeping select features and discarding features with non-matching, empty, missing, and/or null values

How does it work?

Once connected, the AttributeFilter lets you select an attribute to filter incoming features by. By default, Empty, Missing, Null, and Unfiltered outputs are provided, and you can specify additional values to filter by either entering them manually or importing values from an existing dataset.

All features are passed through the transformer, exiting via the appropriate output port.

Cached Values and Data-Aware Attributes

If Feature Caching is enabled, available attribute values from upstream features may be viewed and selected through the Import > From Feature Cache... option.

Examples

Usage Notes

Ideally, you will want to keep the filter list fairly small; otherwise you can end up with a very long list of attributes. If FME determines that the list might be too large, it will return a warning.
If feature filtering can be done with groups or ranges of values, consider using the TestFilter or AttributeRangeFilter.
If you are filtering features for the sole purpose of writing to separate layers or datasets, consider using Fanout instead.
Feature ordering may be specified with the Advanced > Preserve Feature Order parameter.

Configuration

Input Ports

Output Ports

Default Ports

<Empty>	If the feature’s attribute value is an empty string, the feature is output via the <Empty> port.
<Missing>	If the feature does not have the specified attribute, it is output via the <Missing> port.
<Null>	If the feature’s attribute has a value of null, the feature is output via the <Null> port.
<Unfiltered>	If the feature’s attribute has a value not in the list, the feature is output via the <Unfiltered> port. This port can be used for collecting all features with "positive" values, that is, values that are not missing, null, or empty.

Parameters

Advanced

Preserve Feature Order

This parameter controls the order in which features exit a transformer.

When a transformer has more than one output port, features usually exit one port at a time. At times, it may be useful to keep the order that features arrived in, switching from port to port as necessary. This allows feature order to be preserved, though at a potential cost in processing efficiency.

Select a method for feature ordering.

Per Output Port (Default)

Only preserve the input order of features as they occur within the group of features exiting a given output port.

All features exiting an output port retain their ordering relative to each other (within the group), but not relative to features exiting other output ports.

This option is generally the most efficient, where large chunks of features will exit an output port together (taking advantage of bulk mode).

As features exiting different output ports may not be strictly output in the order they arrived, output ordering may be unpredictable.

Across Output Ports

Strictly preserve the input order of features, regardless of which output port they exit. Features will be output singly in the same order they arrived, switching from port to port as necessary. This option is generally less efficient as the processing gains of bulk mode are less likely to apply - however, feature order is predictable.

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.

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.

Content Types

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.

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:

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.

Reference

Processing Behavior	Feature-Based
Feature Holding	No
Dependencies	None
Aliases
History

FME Community

The FME Community is the place for demos, how-tos, articles, FAQs, and more. Get answers to your questions, learn from other users, and suggest, vote, and comment on new features.

Search for all results about the AttributeFilter on the FME Community.

Examples may contain information licensed under the Open Government Licence – Vancouver and/or the Open Government Licence – Canada.