Explodes each list member on each input feature out into its own feature.
Any attributes on the list are demoted to become non-list attributes of the feature output. In addition, the element number of the attributes in the original list is added to the feature. Each feature's output has a copy of the geometry from the original input feature.
Input Ports
Input
Features containing list members.
Output Ports
Elements
If the list is found in the input feature, it will be processed based on Accumulation Mode and output via this port.
<Rejected>
If the list is not found in the input feature, the feature will be output via this port without being processed. In this case, the Accumulation Mode parameter will not be applied and the transformer will pass the feature through without processing it.
Parameters
List Attribute
The name of the list that will be exploded by this transformer.
Element Index Attribute
If the Element Index Attribute is specified, then each element feature output will be given an attribute containing the element's list position.
Attribute Accumulation
If attributes on the incoming and original feature share the same name, but are not geometry attributes that start with fme_, then they are deemed conflicted.
Accumulation Mode
Merge Incoming List: The original feature will retain all of its own un-conflicted attributes, and will additionally acquire any un-conflicted attributes that the incoming list feature has. This mode will handle conflicted attributes based on the Conflict Resolution parameter.
Prefix Incoming List: The original feature will retain all of its own attributes. In addition, the original will acquire attributes reflecting the incoming feature’s attributes, with the name prefixed with the Prefix parameter.
Only Use Incoming List: The original feature will have all of its attributes removed, except geometry attributes that start with fme_. Then, all of the attributes and associated values of the incoming feature will be placed onto the original.
Conflict Resolution
Use Original: If a conflict occurs, the original values will be maintained.
Use Incoming List: If a conflict occurs, the values of the incoming list will be transferred onto the original.
Prefix
If the Accumulation Mode parameter is set to Prefix Incoming List, this value will prefix attributes that are being added to the original feature from the incoming feature.
Usage Notes
- If Input attributes and list element attributes have the same name, the Input attributes will be overwritten by the list element attributes.
- ListExploder will not work with an invalid list, such as one that doesn't start at entry 0. For example:
| Valid List | Invalid List |
| mylist{0}.attr1 | mylist{1}.attr1 |
| mylist{1}.attr1 | mylist{2}.attr1 |
| mylist{2}.attr1 | mylist{3}.attr1 |
| mylist{3}.attr1 | mylist{4}.attr1 |
Examples
Example 1:
If this feature enters this transformer:
somelist{0}.length = 7.3
somelist{0}.kind = ’paved’
somelist{1}.length = 8.4
somelist{1}.kind = ’smooth’
somelist{1}.lanes = 2
somelist{2}.length = 1.1
somelist{2}.kind = ’rough’
another_attr = ’something else’
then, presuming that the list name specified was somelist{}, the index attribute was element_num, and the Accumulation Mode parameter was set to Merge Incoming List, the first returned feature would look like:
length = 7.3
kind = ’paved’
element_num = 0
another_attr = ’something else’
If the Accumulation Mode parameter was set to Only Use Incoming List, the first returned feature would look like:
length = 7.3
kind = ’paved’
element_num = 0
Example 2:
Suppose you have a Input feature with the following 6 attributes. (The List Attribute used here would be ID{}.)
Name
Type
ID{0}.dec
ID{0}.hex
ID{1}.dec
ID{1}.hex
Merge Incoming List will produce elements with 4 attributes:
Name
Type
dec
hex
Only Use Incoming List will produce elements with 2 attributes:
dec
hex
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.
Transformer Categories
Additional Resources
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