Networkx & Gephi Tutorial#pydata

Gilad Lotan | @gilgul

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OSU Students

Ohio based Media

• Node network properties– from immediate connections

• indegreehow many directed edges (arcs) are incident on a node

• outdegreehow many directed edges (arcs) originate at a node

• degree (in or out)number of edges incident on a node

– from the entire graph• centrality (betweenness, closeness)

outdegree=2

indegree=3

degree=5

Source: Lada Adamic (SI508-F08)

Example Graph Types

• Complete Graph

• Bipartite Graph– Vertices can be divided into two disjoint sets– Ex: students & schools

Social Network Attributes• Scale Free

– Degree distribution follows a power law– Barabasi et al (‘99): mapped the topology of a portion of

the web

• Small World– Most nodes are not neighbors, but can be reached by

small number of hops– Watts & Strogatz (’98)– Properties: cliques, sub networks with high clustering

coefficient, most pairs of nodes connected by at least one short path

(Zachary) Karate club graph

social network of friendships between 34 members of a karate club at a US university in the 1970s.

Standard test network for clustering algorithms -> during the observation period the club broke up into two separate clubs over a conflict.

Graph Measures• Centrality

– Betweenness– Closeness– Eigenvector– Degree

• Clustering Coefficient (clique)• Modularity

Graph Layout• Open Ord

– Better distinguishes clusters• Yifan Hu• Force Atlas• Fruchterman Reingold

– Graph as a system of mass particles (nodes:particles, edges:springs)

Networkx

Graph Generators

Generate Twitter Graph

graphml file

nodes

edges

Twitter Users with Python in their Bios

• 2 days of Twitter data (Oct 24th and 25th)• Total: 4246 users (62k tweets)• @mikanyan1 tweeted 795 times

Pythonistas on Twitter

Pythonistas on Twitter

English / European

Japanese

Python(the snake)

Chinese

Spanish Speakers

Musicians, Artists

Twitter User Community: Data Science

• Grepped from Twitter bios over 1 week: "data science|data scientist|machine learning|data strateg”

• 1053 Users• 14k Tweets• Most tweeting users:

– @data_nerd (659)– @Chantel_Esworth (562)– @Da5_12 (253)

Dataists on Twitter

Thank You

Gilad LotanTwitter: @gilgul

Github: giladlotan