[R] Removing a space from a string

[Rasmus Liland]

Dear Dennis,

On 2020-07-28 13:20 -0700, Dennis Fisher wrote:
| Colleagues
| 
| I have strings that contain a space in 
| an unexpected location.  The intended 
| string is:
| 	“STRING 01.  Remainder of the string"
| However, variants are:
| 	“STR ING 01.  Remainder of the string"
| 	“STRIN G 01.  Remainder of the string"
| 
| I would like a general approach to 
| deleting a space, but only if it 
| appears before the period.  Any 
| suggestions on a regular expression 
| for this?

Perhaps by using gregexpr to look for 
dots, remove spaces from the substring until the first 
finding, then pasting it back.

	strings <- 
	c("STRING 01.  Remainder of the string.",
	  "STR ING 01.  Remainder of the string.",
	  "STRIN G 01.  Remainder of the string.")
	
	search <- gregexpr("\\.", strings)
	lens <- nchar(strings)
	FUN <- function(i, strings, search, lens) {
	  before.dot <- substr(strings[i], 1, search[[i]][1])
	  before.dot <- gsub(" ", "", before.dot)
	  after.dot <- substr(strings[i], search[[i]][1]+1, lens[i])
	  return(paste0(before.dot, after.dot))
	}
	simplify2array(parallel::mclapply(
	  X=1:length(strings),
	  FUN=FUN,
	  strings=strings,
	  search=search,
	  lens=lens))

yields

	[1] "STRING01.  Remainder of the string."
	[2] "STRING01.  Remainder of the string."
	[3] "STRING01.  Remainder of the string."

Yes, I know, the space just before 01 
also disappears ... 

Best,
Rasmus