CODEWITHSUNDEEP
pythonnetworkxgraphvizpygraphviz
J Cena
J Cena

Reputation: 1053

Using networkX to output a tree structure

I am using networkX to generate a tree structure as follows (I am following the answer of this question).

import networkx as nx
import matplotlib.pyplot as plt
G = nx.DiGraph()

G.add_node("ROOT")
for i in range(5):
    G.add_node("Child_%i" % i)
    G.add_node("Grandchild_%i" % i)
    G.add_node("Greatgrandchild_%i" % i)

    G.add_edge("ROOT", "Child_%i" % i)
    G.add_edge("Child_%i" % i, "Grandchild_%i" % i)
    G.add_edge("Grandchild_%i" % i, "Greatgrandchild_%i" % i)

# write dot file to use with graphviz
# run "dot -Tpng test.dot >test.png"
nx.write_dot(G,'test.dot')

# same layout using matplotlib with no labels
plt.title('draw_networkx')
pos=nx.graphviz_layout(G, prog='dot')
nx.draw(G, pos, with_labels=False, arrows=False)
plt.savefig('nx_test.png')

I want to draw a tree as in the following figure. enter image description here

However, I am getting an error saying AttributeError: module 'networkx' has no attribute 'write_dot'. My networkx version is 1.11 (using conda). I tried different hacks, but none of them worked.

So, I am interested in knowing if there is another way of drawing tree structures using networkx to get an output similar to the one mentioned in the figure. Please let me know.

Upvotes: 5

Views: 10537

Answers (2)

Anil_M
Anil_M

Reputation: 11443

You can draw digraph entirely with pygraphviz.

Following steps needs to be followed first as pygraphviz does not work without graphviz (as of now).

  1. Download graphviz-2.38.msi from http://www.graphviz.org/Download_windows.php and install
  2. Download the 2.7 or 3.4 pygraphviz wheel file from http://www.lfd.uci.edu/~gohlke/pythonlibs/#pygraphviz
  3. Navigate to the directory that you downloaded the wheel file and run your platform specific wheel pip install pygraphviz‑1.3.1‑cp34‑none‑win32.whl
  4. Add dot.exe to host path e.g. on windows control-panel ->system -> edit environment variables -> Modify PATH

After that dot and png files can be created as below.

Working Code

import pygraphviz as pgv

G=pgv.AGraph(directed=True)

#Attributes can be added when adding nodes or edge
G.add_node("ROOT", color='red')
for i in range(5):
    G.add_node("Child_%i" % i, color='blue')
    G.add_node("Grandchild_%i" % i, color='blue')
    G.add_node("Greatgrandchild_%i" % i, color='blue')

    G.add_edge("ROOT", "Child_%i" % i, color='blue')
    G.add_edge("Child_%i" % i, "Grandchild_%i" % i, color='blue')
    G.add_edge("Grandchild_%i" % i, "Greatgrandchild_%i" % i, color='blue')

# write to a dot file
G.write('test.dot')

#create a png file
G.layout(prog='dot') # use dot
G.draw('file.png')

PNG File
enter image description here

Upvotes: 2

Tzomas
Tzomas

Reputation: 704

I think this issue was solved on networkx 2.x, but before that you should be explicit import of the function like this.

from networkx.drawing.nx_agraph import write_dot

or

from networkx.drawing.nx_pydot import write_dot

I hope this works.

Upvotes: 2

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