[R] plot and factors

From: Jason Miller <millerj_at_truman.edu>
Date: Fri 02 Dec 2005 - 23:40:48 EST

Read R-helpers,

I'm relatively new to R and trying to jump in feet first. I've been able to learn a lot from on-line and printed documentation, but here's one question to which I can't find an answer. Well, it's a question with a couple parts. Thanks in advance for any direction
(partial or complete) that anyone can provide.

I have a data frame with three columns: Year, Semester, value1. I want to treat Year and Semester as factors; there are many years, and there are three semesters (Fall, Spring, Summer).

First, I would like to be able to plot the data in this frame as Year v. value with one curve for each factor. I have been unable to do this. Is there any built-in R functionality that makes this easy, or do I need to build this by hand (e.g., using the techniques in FAQ 5.11 or 5.29)?

Second, I would like to be able to plot the values against a doubly labeled axis that uses Year and Semester (three Semester ticks per Year). Is there a relatively straightforward way to do this?
(What's happening, of course, is that I'd like to treat Year+Semester
as a single factor for the purpose of marking the axis, but I'm not sure how to do that, either.)

Again, thanks for whatever pointers people can share.

Jason

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Jason E. Miller, Ph.D.
Associate Professor of Mathematics
Truman State University
Kirksville, MO
http://pyrite.truman.edu/~millerj/
660.785.7430

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https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Fri Dec 02 23:52:11 2005