Question

I’m working through an R tutorial. Currently I’m making histograms. As the tutorial progresses it asks for changes to the already constructed histograms – add an xlab, add main etc etc.

That’s fine except each time I have to create the histogram from scratch.

How does one edit existing rather than write out all the code again? Would it be a matter of making the histogram an object and just editing it each time? I tried that. Lets say I start with this:

hearthist <- hist(outcome[,11])

I then want to add an xlabel. I tried this with no joy:

hearthist (xlab="30-Day Death Rate")

Whats the best practice here? Do I need to recreate a fresh histogram each time I want to add a parameter?

Answer 1

No; base graphics use a pen on paper idiom; once you make a mark that is it until you get a new piece of paper.

So, use to learn the appropriate tools. In this case an R-aware editor that you can write your R code and pipe it into a running R instance. I use ESS with Emacs, but the kool kids use RStudio. Give the latter a go.

Even standard, plain old R has a history mechanism which allows you to scroll back through your commands and re-run them from the command line.

Or learn to use the appropriate R tools. title() allows you to add xlab, ylab, main, and sub to an existing plot.