But why the goal would be to remove the last letter?

Am I missing something, or kata description, or anything, does not mention letters anywhere?

i meant that if the goal is removing last letter it won't work, because as you said php will count space as a caracter and we never can remove last letter because it will only remove spaces at the end of string . i hope i could exprime myself well.

How is space different from any other character?

what if we have a string that has some space at the end of it!

really cool!

nice and concise!

Clean as f