Recently I discovered IPython notebook which is a powerful tool. As an IT student, I was looking for a way to represent graphs in Python. For example, I would like to know if there's a library (like numpy or matplotlib ?) which can draw from this

{ "1" : ["3", "2"],"2" : ["4"],"3" : ["6"],"4" : ["6"],"5" : ["7", "8"],"6" : [],"7" : [],"8" : []
}

something like this :

Is there something like this ?

You can use networkx and, if you need to render the graph in ipython notebook, nxpd

import networkx as nx
from nxpd import draw
G = nx.DiGraph()
G.graph['dpi'] = 120
G.add_nodes_from(range(1,9))
G.add_edges_from([(1,2),(1,3),(2,4),(3,6),(4,5),(4,6),(5,7),(5,8)])
draw(G, show='ipynb')