Append newlines to the end of strings.
Arguments
- txt
 A vector of character strings.
- start_par
 Add a newline at the beginning of the string. If there is more than one string in
txt,start_parshould have length 1 or the length oftxt.- extra_lines
 The number of blank lines to follow the string. If there is more than one string in
txt,extra_linesshould have length 1 or the length oftxt.- collapse
 Collapse all strings in
txtinto a single string after appending newlines. This can bee logical, in which case the collapsed strings are separated by an empty string, or it can be a character string.
Details
Take a character vector, ensure that each element ends in a newline, Optionally add an extra newline to the beginning of each element, add extra blank lines at the end, and optionally concatenate the elements together into a single string, separated by an optional separator in addition to the new lines.
Examples
append_newline_if_needed("foo")
#> [1] "foo\n"
append_newline_if_needed("foo", start_par = TRUE)
#> [1] "\nfoo\n"
append_newline_if_needed("foo", extra_lines = 3)
#> [1] "foo\n\n\n\n"
append_newline_if_needed(month.abb, start_par = c(TRUE, rep(FALSE, 11)),
  collapse = TRUE)
#> [1] "\nJan\nFeb\nMar\nApr\nMay\nJun\nJul\nAug\nSep\nOct\nNov\nDec\n"
append_newline_if_needed(month.abb, collapse = "...")
#> [1] "Jan\n...Feb\n...Mar\n...Apr\n...May\n...Jun\n...Jul\n...Aug\n...Sep\n...Oct\n...Nov\n...Dec\n"
append_newline_if_needed(c("Months:", month.abb, extra_lines = 0,
  collapse = "* "))
#>  [1] "Months:\n" "Jan\n"     "Feb\n"     "Mar\n"     "Apr\n"     "May\n"    
#>  [7] "Jun\n"     "Jul\n"     "Aug\n"     "Sep\n"     "Oct\n"     "Nov\n"    
#> [13] "Dec\n"     "0\n"       "*\n"