Creates value pairs (attribute name and attribute value) for every attribute on a feature, and either adds them to a list attribute or creates new features (one for each pair) with new attributes containing both values.

In either case, original attributes and geometry may be kept or discarded.

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Typical Uses

  • Transposing or manipulating tabular data (such as spreadsheets)
  • Melting data
  • Extracting the attribute schema from features for use in dynamic translation attribute mappings
  • Extracting the attribute schema from features to write as metadata/documentation
  • Preparing data for charts and reports

How does it work?

The AttributeExploder receives features with attributes, and extracts both the attribute names and their values. It can do one of two things with them (the Exploding Type) - either create multiple new features (one for each attribute), or add the information to the original feature as a list attribute.

The following examples demonstrate both Exploding Types, as they apply to a single feature. Note that in both cases, extra attributes that are normally unexposed are also exploded, including reader and internal fme_ attributes.

You may opt to either keep or discard the original attributes and geometry - in these examples, they are discarded.

Exploding Type: Features

If the attributes are exploded into Features, each input feature will become many - one for every attribute in the original feature. The new features will have both the original attribute names and values added as new attributes. Below, we use the default new attribute names _attr_name and _attr_value.

One (1) feature becomes twelve (12).

In the case of a spreadsheet, where a row is considered a single feature, this is the equivalent of exploding every cell into its own feature.

Exploding Type: List

If the attributes are exploded into a List, a new list attribute is added to the original feature.

The attribute names and values are added as list elements.

One (1) feature in produces one (1) feature out, with a list attribute.

Excluding Attributes

AttributeExploder processes all attributes on incoming features, including fme_ and format attributes. It is possible to ignore attributes using the Ignore Attributes Containing parameter.

Enter a regular expression, and matching attributes will be ignored.

For example, if the source data is CSV, you could use the regular expression ^fme_|^multi_|^csv_ to ignore any attributes starting with fme_, multi_, or csv_.


Usage Notes

  • The AttributeExploder is commonly used in manipulating tabular data, from simple transposition to more complex tasks. See articles on the FME Community for detailed examples.
  • To unmelt (reverse melt) data, see the AttributeCreator (alias UnMelter).


Input Ports

Output Ports


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.

Dialog Options - Tables

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


Processing Behavior


Feature Holding


Dependencies None
Aliases Melter

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 AttributeExploder on the FME Community.


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