Ni! Hi Haiko,
GraphView can simultaneously take `vfilt` and `efilt` parameters, if that
is what you wanna know. So,
g_filter = GraphView(g, vfilt=vp_filter, efilt=ep_filter)
should work just fine.
Regarding your code snippet, the 'elegance' issues are kinda unrelated to
graph_tool. For example, in the second part, you iterate the dataframe
instead of simply iterating the graph edges and getting the edge layer from
the internal property map. You also use an if clause to assign the boolean
value of the if clause, instead of directly assigning it. So, this is
equivalent to your `for` loop:
for e in g.edges():
ep_filter[e] = g.edge_properties['layer'][e] == layer
All the best,
.~´
On Thu, Aug 29, 2019 at 10:49 AM Lietz, Haiko <[email protected]> wrote:
> Hi all,
>
>
>
> gt allows creating graph views where vertices and/or edges are filtered
> out. The principle is described in the documentation:
>
>
>
> "Vertices or edges which are to be filtered should be marked with a
> PropertyMap with value type bool, and then set with set_vertex_filter() or
> set_edge_filter() methods. By default, vertex or edges with value '1' are
> kept in the graphs, and those with value '0' are filtered out." (
> https://graph-tool.skewed.de/static/doc/quickstart.html#graph-filtering)
>
>
>
> Given a layered graph, where layers are coded via an edge property, I want
> to draw the graphs layer by layer.
>
>
>
> This is an example graph:
>
> from graph_tool.all import *
>
> import numpy as np
>
> import pandas as pd
>
> # data
>
> edge_list = pd.DataFrame(np.array([[0, 1, 0], [1, 2, 1], [2, 0, 2]]),
> columns=['i', 'j', 'layer'])
>
> # create graph
>
> g = Graph(directed=False)
>
> ep_layer = g.new_edge_property('int')
>
> g.add_edge_list(edge_list.values, eprops=[ep_layer])
>
> g.edge_properties['layer'] = ep_layer
>
> # draw graph with edge colors showing the layers
>
> graph_draw(g, edge_color=g.ep.layer)
>
>
>
> It is possible to draw a single layer (in this example layer 0) in this
> complicated way:
>
>
>
> # set layer to be drawn
>
> layer = 0
>
> # create graph view
>
> ep_filter = g.new_edge_property('bool')
>
> for i in range(0, len(edge_list)):
>
> e = g.edge(edge_list['i'][i], edge_list['j'][i])
>
> if edge_list['layer'][i] == layer:
>
> ep_filter[e] = True
>
> else:
>
> ep_filter[e] = False
>
> g_filter = GraphView(g, efilt=ep_filter)
>
> # draw filtered graph
>
> graph_draw(g_filter, edge_color=g.ep.layer)
>
>
>
> If I proceed this way I will also have to create a vertex property map to
> filter unused vertices and do these steps for all layers I want to draw.
>
>
>
> But isn’t there a more elegant way – preferably handling vertices and
> edges in the same step?
>
>
>
> Many thanks and best wishes
>
>
>
> Haiko
>
>
>
>
> _______________________________________________
> graph-tool mailing list
> [email protected]
> https://lists.skewed.de/mailman/listinfo/graph-tool
>
_______________________________________________
graph-tool mailing list
[email protected]
https://lists.skewed.de/mailman/listinfo/graph-tool
