Python igraph: delete vertices from a graph

Question

I am working with enron email dataset and I am trying to remove email addresses that don't have "@enron.com" (i.e. I would like to have enron emails only). When I tried to delete those addresses without @enron.com, some emails just got skipped for some reasons. A small graph is shown below where vertices are email address. This is gml format:

Creator "igraph version 0.7 Sun Mar 29 20:15:45 2015"
Version 1
graph
[
  directed 1
  node
  [
    id 0
    label "[email protected]"
  ]
  node
  [
    id 1
    label "[email protected]"
  ]
  node
  [
    id 2
    label "[email protected]"
  ]
  node
  [
    id 3
    label "[email protected]"
  ]
  node
  [
    id 4
    label "[email protected]"
  ]
  node
  [
    id 5
    label "[email protected]"
  ]
  node
  [
    id 6
    label "[email protected]"
  ]
  node
  [
    id 7
    label "[email protected]"
  ]
  node
  [
    id 8
    label "[email protected]"
  ]
  node
  [
    id 9
    label "[email protected]"
  ]
  edge
  [
    source 5
    target 5
    weight 1
  ]
]

My code is:

G = ig.read("enron_email_filtered.gml")
for v in G.vs:
    print v['label']
    if '@enron.com' not in v['label']:
        G.delete_vertices(v.index)
        print 'Deleted'

In this dataset, 7 emails should be deleted. However, based on the above code, only 5 emails are removed.

Answer 1

From the tutorial here, you can access all the vertices with a specific property, and then delete them in bulk as follows:

to_delete_ids = [v.index for v in G.vs if '@enron.com' not in v['label']]
G.delete_vertices(to_delete_ids)

Here is the output I got:

to delete ids: [1, 3, 4, 5, 7, 8, 9]
Before deletion: IGRAPH D-W- 10 1 --
+ attr: id (v), label (v), weight (e)
+ edges:
5->5
After deletion: IGRAPH D-W- 3 0 --
+ attr: id (v), label (v), weight (e)
label: [email protected]
label: [email protected]
label: [email protected]