Re: [igraph] writing a layout in a format

[Tamas Nepusz]

> I was wondering if someone could provide an example of how to write  
> the layout in python.
Well, there are no predetermined layout formats in igraph, so you can  
use whatever format suits you the best. If you want to read the layout  
from other applications later, it's maybe the best to simply write the  
x-y coordinates one per line as follows, e.g.:

g = Graph.GRG(100, 0.2)
layout = g.layout("kk")
fp = file("layout.dat", "w")
for x, y in layout:
  print >>fp, x, y
fp.close()

Another way to go is to store the X and Y coordinates as vertex  
attributes and then save the graph in a format that preserves vertex  
attributes, e.g.:

g = Graph.GRG(100, 0.2)
layout = g.layout("kk")
g.vs["x"], g.vs["y"] = zip(*layout)        # ugly but neat trick
g.write("my_graph.graphml")

The same should also work with "my_graph.gml" (using the GML format  
instead of GraphML) or "my_graph.pickle" (uses Python's pickle module  
instead of GraphML).

> You guys need more examples of the simple stuff.   :-)
Yes I know ;) The Python docs definitely need some improvement (and I  
definitely need some spare time to improve the docs). Sorry about  
that. Hope this helps.

--
Tamas


> I'm trying to follow the documentation "write(self, f, format =None,  
> *args, **kwds ) " but I don't know what the heck I'm doing.
>
> Thanks,
> - Jeff
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