Converting sequence expression to a string in R plot label

Question

ab <- 1:4
plot(ab, main = paste("value",ab))

The above produces

Whereas I want the label to show exactly like value 1:4. I know I can do this by tweaking the paste function something like paste0("value ",ab[1],":", ab[4]). But there must be a simpler way and also sometimes ab is just a single number, so I want something consistent that works for both cases. I also tried with expression and bquote, but can't figure out a way. Thanks.

question from:https://stackoverflow.com/questions/65921262/converting-sequence-expression-to-a-string-in-r-plot-label

Answer 1

You can use range(ab) and a second paste (with collapse=':') to get this result. For the case where ab is a single value, I had to use ifelse.

EDIT: a slightly shorter solution using unique instead of ifelse to treat for the case with a single value

ab <- 1:4
plot(ab, main = paste("value", paste(unique(range(ab)), collapse = ':')))

If ab = 1: