I'm using networkx very superficially. It's easy to write a graph to a file, like graphml, but how can I save it into a string without bothering the file system?
Its doc says it is possible.
Most of the formats also have a "generator". So you can do it this way without using StringIO:
In [1]: import networkx as nx
In [2]: G=nx.path_graph(4)
In [3]: s='\n'.join(nx.generate_graphml(G))
In [4]: print s
<graphml xmlns="http://graphml.graphdrawing.org/xmlns" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://graphml.graphdrawing.org/xmlns http://graphml.graphdrawing.org/xmlns/1.0/graphml.xsd">
<key attr.name="name" attr.type="string" for="graph" id="d0" />
<graph edgedefault="undirected">
<data key="d0">path_graph(4)</data>
<node id="0" />
<node id="1" />
<node id="2" />
<node id="3" />
<edge source="0" target="1" />
<edge source="1" target="2" />
<edge source="2" target="3" />
</graph>
</graphml>