Feature #15496
Updated by macdevign (Macdevign mac) over 5 years ago
I could not find the a simple String api to extract the string between two string, and I notice that many face the same issue and endup rolling their own solutions (eg https://stackoverflow.com/questions/9661478/how-to-return-the-substring-of-a-string-between-two-strings-in-ruby). Given that string "between" extraction is such a common operation, will adding a focused and simplified String method make coding pleasant ? This is my solution but probably someone can provide better and efficient implementation. ~~~ # self: String instance, # from: String -> first 'from' String # to: String -> first 'to' String found after 'from' # ignore_case: Boolean -> to indicate case-sensitive search # from_index: Integer -> Position of 'From' string to start search from # return string between from and to, which exclude the argument, nil otherwise. def between(from, to, ignore_case: false, from_index: 0) to) str = self str, from, to = str.downcase, from.downcase, to.downcase if ignore_case from_idx = str.index(from, from_index)&.+(from.length) self.index(from)&.+(from.length) if from_idx to_idx = str.index(to, self.index(to, from_idx) return str[from_idx...to_idx] self[from_idx...to_idx] if to_idx end nil end ~~~ Test case "Hello world".between("ell", "ld") => "o wor" "Testing 123".between("Te", "123") => "sting " "Testing 123".between("te", "123") => nil "Testing 123".between("te", "123", ignore_case: true) => "sting " "Testing 123".between("te", "123", from_index: 3) => nil