I ended up using a string
data type to encode the data within the array. There is no native way to represent iterable data types with this format at the time of this posting. Here is an example of a node
attribute with an array of values associated with it, in graphml format:
<graphml
<!-- Boilerplate graphml -->
<key id="v_arr" for="node" attr.name="arr" attr.type="string"/>
<graph id="G" edgedefault="undirected">
:
:
<node id="n0">
<data key="v_arr">23 4 5</data>
</node>
<node id="n1">
<data key="v_arr">34.3 53.34</data>
</node>
<node id="n2">
<data key="v_arr">45.4 23E-23</data>
</node>
<edge source="n0" target="n2">
</edge>