sorry, I wasnt sure
The enumerate operator returns the index and the value (a tuple in python terms), which in this case is the index and the lowercase version of the value. Because l1lcase and l1 are parallel arrays, the l1[idx] gets the equivalent item for the one in l1lcase, which is the cased version.
Great thanks, i wanted to code something like that but unsure how in this language, very frustrating.
I come up with a slightly different way of doing it, posted a minute before your reply so not sure if you saw it, its probably laughable mind you