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UPDATED: Why didn’t the isolates go away?

I’m giving in. I’m finally learning how to do social network analysis R. What made me switch (from only UCINet and NodeXL)? Well, all my data lives in a MySQL database, and I have networks with millions of edges. R makes it really easy to connect to MySQL and create a data frame from data found there. That saves me about 20 minutes every time I want to do some analysis. No more selecting and downloading data and crashing UCINet and Excel, just

con <- dbConnect(MySQL(), user="user", password="pass", dbname="TwitterCollector", host="localhost")

mentions <- dbGetQuery(con, "SELECT * FROM tweet_mentions WHERE source_user_id IN (SELECT user_id FROM congress_attributes) AND target_user_id IN (SELECT user_id FROM congress_attributes)")

And I have all of Congress’s mentions of one another ready to go. Phew!

All I did today was get those connections setup, get some data in data frames for R to use, and then draw some rudimentary graphs like this one:

Mentions - Full network

I’m glad to see output, but I’m confused about why my isolate deleting functions didn’t work. Here’s how I tried to delete isolates:

mention_graph_no_iso <- delete.vertices(mention_graph, V(mention_graph)[degree(mention_graph)==0])

But I still see isolates in my graph. In fact, this one is even messier:

Mentions - no isolatesUPDATE:

The isolates weren’t in the graph object, but I forgot to rerun the layout after removing them. So, once I did that, I got a less messy graph (see below). I also cleaned up my code by moving the deleting isolates code to a function. I got the original function online but can’t find the page. Will post the URL here when I do. I made a small change to the function, and here it is:

delete.isolates <- function(graph, mode = 'all') {
isolates <- which(degree(graph, mode = mode) == 0)
delete.vertices(graph, isolates)


So, what do you think ?

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