# ggplot2 joy

February 25, 2011
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(This article was first published on Stat Bandit » R, and kindly contributed to R-bloggers)

I’ve been working on a long-term (25+yr) longitudinal study of rheumatoid arthritis with my boss. He just walked in and asked if I could create a plot showing the trajectory of pain scores over time for each subject, separated by educational level (4 groups). Having now worked with ggplot2 for a while, and learning more at the last two DC useR meetups, I realized that I could formulate this in ggplot very easily and in short order. Hooray!!! Basically, all I needed to do was:
 ggplot(data, aes(time, pain, groups=patient.id, color=education.level))+geom_line() 
I actually spent more time figuring out how to change the legend title (fyi, it is + labs(colour='Education'), with the British spelling being necessary).

I’m actually pretty thrilled that I could use ggplot2 on short order to make this plot.

On another note, my friend Brian Danielak gave a brilliant presentation at last night’s DC R Users meetup on some ggplot2-based development he’s doing for graphical ANOVA. A link to his talk should be on the meetup.com site in short order, so please do check it out.