Question

I am plotting a continuous variable against a factor using plot() in R (see example below). I do not want the labels on the axes. Without the as.factor call in the formula ann = F suppresses the printing of the labels but it doesn’t work with as.factor in the formula.

Why is this?

Thank you.

# example for SO
# example data 
x <- sample(1:100, 10)
y <- c(rep(1, 5), rep(2, 5))

# ann = F doesn't work here
plot(x ~ as.factor(y), ann = F)

# ann = F does work here
plot(x ~ y, ann = F)

Answer 1

It seems to be caused by plot.formula because it works if you specify x and y separately:

plot(as.factor(y), x, ann=FALSE)

UPDATE:

Confirmation that it’s in graphics:::plot.formula. The line that calls plot explicitly sets ylab and xlab (funname is "plot" and dots = list(ann=FALSE)):

do.call(funname, c(list(mf[[i]], y, ylab = yl, xlab = xl), dots))