regex - R split on delimiter (split) keep the delimiter (split)

Question

In R you can use the strsplit function to split a vector on a delimiter(split) as follows:

x <- "What is this?  It's an onion.  What! That's| Well Crazy."
unlist(strsplit(x, "[\?\.\!\|]", perl=TRUE))

## [1] "What is this"    "  It's an onion" "  What"          " That's"        
## [5] " Well Crazy"

I'd like to keep the delimiter(split) using R. So the desired output would be:

## [1] "What is this?"    "  It's an onion." "  What!"          " That's|"        
## [5] " Well Crazy."

Answer 1

You can use "(?<=DELIMITERS)":

unlist(strsplit(x, "(?<=[?.!|])", perl=TRUE))

## [1] "What is this?"    "  It's an onion." "  What!"          " That's|"        
## [5] " Well Crazy.