ggplot2: Splitting facet/strip text into two lines

ggplot2 supports a built in way of doing this using label_wrap_gen.

x <- c(1:3, 1:3)y <- c(3:1, 1:3)grp = c(rep("group 1 with a long name",3),rep("group 2 with a long name",3))d = data.frame(x = x, y =y, grp = grp)ggplot(d, aes(x=x,y=y)) + geom_line() + facet_wrap(~ grp, labeller = label_wrap_gen(width=10))

You can use a 2-line label:

grp <- c(rep("foo\nbar",3), 1, 1, 1)qplot(x=x, y=y) + geom_line() + facet_wrap(~ grp)

I tried this a variety of ways but was frustrated getting the paste(strwrap(text, width=40), collapse=" \n") to give me results for the single row of data and not concatenate the each bit of text from the entire list.

I came up with a solution that worked best for me. I wrote a function like the one below. Given a dataframe data with column text

wrapit <- function(text) {  wtext <- paste(strwrap(text,width=40),collapse=" \n ")  return(wtext)}data$wrapped_text <- llply(data$text, wrapit)data$wrapped_text <- unlist(data$wrapped_text)

After I called this function, I just applied my labeller function to the wrapped_text column instead of the text column.