Search for the last match inside text. Returns the position number or -1 if not found.
look in (text): the text to search inside
look for (text): the text that will be searched for
right-most position (number): optional - the right-most position to search, where 0 is the first position
- position (number): the position of the last match, where 0 is the first position. Returns -1 if there is no match.
If look in is "Mississippi":
If look for is "ss" and right-most position is not provided, then position is 5. (the position of second "ss")
If look for is "ss" and right-most position is 4, then position is 2. (searches only "Missi" - stops at position 4)
If look for is "abc", then position is -1. (not found)