Write x̄ (meaning average) in legend and how to prevent linebreak?

Question

Good day!

I am not that familiar to R so I'd be glad to get a little help.

Assume I have the following minimal example:

test <- c(10,20,40,80,80)
avg <- mean(test)
avg <- format(avg,digits=2)

plot(test, xlab="x", ylab="y", pch = 4)
legend("topleft", legend= c("Average: ", avg))

I'd like to write x̄ instead of "average" - wonder if this is event possible as it's not a regular symbol - merely a combination of two (letter plus overline).

The other thing I'd like to get rid of is the line break after the word "Average (see arrow in graphic below):

Answer 1

There are two issues here. The first is that this is handled using ?plotmath in R. The operator you are looking for is bar(). This is not a function but markup that plotmath understands.

The second is that you need an expression in which avg is converted to its value. You need an expression because that is what plotmath works with. There are several solutions to this problem, but the one I use below is bquote(). You provide it an expression and anything wrapped in .( ) will be converted its value by evaluating the thing inside the .( ).

Here is your code and a suitably modified legend() call:

test <- c(10,20,40,80,80)
avg <- mean(test)
avg <- format(avg,digits=2)

plot(test, xlab="x", ylab="y", pch = 4)
legend("topleft", legend = bquote(bar(x)*":" ~ .(avg)))

Do note that this will insert exactly what is in avg. You may need to do

avg <- round(avg)

or some other formatting fix to get something nice and presentable.