How to replace occurences in string using groups in Swift?

Answer 1

You can do a regular expression search, with a template in the replacement string:

let string = "
hello
 my 
Doggy
"
let newString = string.replacingOccurrences(of: "
|
", with: "\n$0", options: .regularExpression)

For each match, the $0 template is replaced by what actually matched the pattern.