Wrapping a string into a set number of lines

Question

I have a set of strings such as

x <- c("xxx", "xxx xxx", "xxx xxxx xxx", "xxx xxxx xxx xxxxxx")

and I want to wrap each so that they fall over two lines, with the breaks where there are spaces, roughly in the middle of the strings, i.e. an output such as

"xxx" "xxx\nxxx" "xxx\nxxxx xxx" "xxx xxxx\nxxx xxxxxx"

I thought strwrap would work, but I cannot figure out how set a width that does will avoid outputs straying on to a third line

What are the exact rules for where the line breaks should be inserted. You haven't actually given us very clear rules here. — Tim Biegeleisen, Aug 07 '21 at 04:30
That doesn't really answer my question. _Which_ spaces, or where should the breaks occur? — Tim Biegeleisen, Aug 07 '21 at 05:25

MrFlick · Accepted Answer · 2021-08-07T17:37:45.863

I don't know of any built in function that does this, but you can find the "middle-most" space and replace it with a new line with a function like this:

two_line_wrap <- function(x) {
  mapply(function(spaces, length, string) {
    if(all(spaces==-1)) return(string);
    breakp <- spaces[which.min(abs(spaces-length/2))]
    substr(string, breakp, breakp) <- "\n"
    string
  }, gregexpr(" ", x), nchar(x), x)
}

two_line_wrap(x)
# [1] "xxx"                  "xxx\nxxx"            
# [3] "xxx\nxxxx xxx"        "xxx xxxx\nxxx xxxxxx"

Wrapping a string into a set number of lines

1 Answers1