Setting any edge key attribute as weight
Stephan Gerhard
A simple use case, but I don't know how I can do most efficiently.
import networkx
G=networkx.path_graph(2)
G.edge[0][1]={'a': 2, 'b': 4}
Now, for analysis, I want to select one key whose value is used as
weight (key).
Is there a simple way to do this?
Stephan
Aric Hagberg
One simple solution is to just assign the 'weight' key.
In [1]: import networkx
In [2]: G=networkx.Graph()
In [3]: G.add_edge(0,1,a=2,b=4)
In [4]: G.edges(data=True)
Out[4]: [(0, 1, {'a': 2, 'b': 4})]
In [5]: for u,v,d in G.edges(data=True):
...: G[u][v]['weight']=d['b']
...:
...:
In [6]: G.edges(data=True)
Out[6]: [(0, 1, {'a': 2, 'b': 4, 'weight': 4})]
In [7]: for u,v,d in G.edges(data=True):
G[u][v]['weight']=d['a']
...:
...:
In [9]: G.edges(data=True)
Out[9]: [(0, 1, {'a': 2, 'b': 4, 'weight': 2})]
Aric
darshan
G.add_edge gives error.
G.add_edge(0,1,a=2,b=4)
TypeError: add_edge() got an unexpected keyword argument 'a'
Please help
Christopher Ellison
> I can't get the simple things of networkx to work
>
> G.add_edge gives error.
> G.add_edge(0,1,a=2,b=4)
> TypeError: add_edge() got an unexpected keyword argument 'a'
>
> Please help
>
Do you have most updated SVN version of NetworkX installed? The above
error suggests that you have an older version.
Chris
darshan
>>> print networkx.__version__
0.36
On Oct 29, 2:36 pm, Christopher Ellison <celli...@cse.ucdavis.edu>
wrote:
Christopher Ellison
> I installed it today through synaptics manager on ubuntu.
>
>>>> print networkx.__version__
> 0.36
>
The version in the Ubuntu repositories is quite old, at least in
comparison to what is on SVN. The new features you are trying to use
require a newer version (something like 1.0rc1). You might try
installing from SVN or easy_install.
Chris
arnegr
On Oct 29, 8:33 pm, Christopher Ellison <celli...@cse.ucdavis.edu>
wrote:
I'm using version 1.0rc1 and have a similar problem. At least I got
the same error message. When creating a layout using pygraphviz I get:
File "/usr/lib/python2.5/site-packages/networkx/drawing/
nx_agraph.py", line 246, in pygraphviz_layout
A=to_agraph(G)
File "/usr/lib/python2.5/site-packages/networkx/drawing/
nx_agraph.py", line 156, in to_agraph
A.add_edge(u,v,**edgedata)
TypeError: add_edge() got an unexpected keyword argument 'weight'
Thanks for help!
Arne
Aric Hagberg
>
> I'm using version 1.0rc1 and have a similar problem. At least I got
> the same error message. When creating a layout using pygraphviz I get:
>
> File "/usr/lib/python2.5/site-packages/networkx/drawing/
> nx_agraph.py", line 246, in pygraphviz_layout
> A=to_agraph(G)
> File "/usr/lib/python2.5/site-packages/networkx/drawing/
> nx_agraph.py", line 156, in to_agraph
> A.add_edge(u,v,**edgedata)
> TypeError: add_edge() got an unexpected keyword argument 'weight'
This is working for me with 1.0rc1. Are you sure you are using
that version? If there is a bug here I'd like to get it fixed.
In [1]: import networkx;networkx.__version__
Out[1]: '1.0rc1'
In [2]: import pygraphviz;pygraphviz.__version__
Out[2]: '1.0.dev1489'
In [3]: G=networkx.Graph()
In [4]: G.add_edge(1,2,weight=7)
In [5]: A=networkx.to_agraph(G)
In [6]: A
Out[6]:
strict graph {
1 -- 2 [weight=7];
}
In [7]: pos=networkx.pygraphviz_layout(G)
In [8]: pos
Out[8]: {1: (28.0, 29.0), 2: (100.0, 19.0)}
Aric
darshan
arnegr
i had an older pygraphviz version (0.35). I updated to 0.99.1 but
still have an error, even if it's not the same than before :-)
0.99.1 is the newest version of pygraphviz I can get on python package
index...where do I get your version '1.0.dev1489'?
This is the message ipython gives, when trying your example:
In [1]: import networkx as nx;nx.__version__
In [2]: import pygraphviz;pygraphviz.__version__
In [3]: G=nx.Graph()
In [4]: G.add_edge(1,2,weight=7)
In [5]: A=nx.to_agraph(G)
/usr/lib/python2.5/site-packages/pygraphviz-0.99.1-py2.5-linux-
x86_64.egg/pygraphviz/agraph.py:1586: DeprecationWarning: raising a
string exception is deprecated
raise "Attribute value must be a string"
---------------------------------------------------------------------------
Attribute value must be a string Traceback (most recent call
last)
/usr/lib/python2.5/site-packages/networkx/drawing/nx_agraph.py in
to_agraph(N)
154 else:
155 for u,v,edgedata in N.edges_iter(data=True):
--> 156 A.add_edge(u,v,**edgedata)
157
158
/usr/lib/python2.5/site-packages/pygraphviz-0.99.1-py2.5-linux-
x86_64.egg/pygraphviz/agraph.py in add_edge(self, u, v, key, **attr)
374 eh=gv.agedge(self.handle,uh,vh,key,_Action.create)
375 e=Edge(self,eh=eh)
--> 376 e.attr.update(**attr)
377 except KeyError:
378 return None # silent failure for strict graph,
already added
/usr/lib/python2.5/UserDict.py in update(self, other, **kwargs)
158 self[k] = v
159 if kwargs:
--> 160 self.update(kwargs)
161 def get(self, key, default=None):
162 try:
/usr/lib/python2.5/UserDict.py in update(self, other, **kwargs)
150 elif hasattr(other, 'iteritems'): # iteritems saves
memory and lookups
151 for k, v in other.iteritems():
--> 152 self[k] = v
153 elif hasattr(other, 'keys'):
154 for k in other.keys():
/usr/lib/python2.5/site-packages/pygraphviz-0.99.1-py2.5-linux-
x86_64.egg/pygraphviz/agraph.py in __setitem__(self, name, value)
1584 pass
1585 except TypeError:
-> 1586 raise "Attribute value must be a string"
1587
1588 def __getitem__(self, name):
Attribute value must be a string: None
In [6]:
Any idea?Thanks in advance...Arne
arnegr
i managed to get the newest pygraphviz version from the subversion
system and I'm glad to tell, that at least your example is working for
me now as well! I think my original problem will be solved now as
well...thanks! Arne