Question

I’m learning Ruby and I’ve seen that an exclamation mark at the end of a method name by convention means that the method modifies self in some way. Why doesn’t then Array#delete end with an exclamation mark, like slice! does, since delete deletes an element from self? Am I missing something fundamental?

Answer 1

To quote Matz (Ruby’s chief engineer):

The bang (!) does not mean “destructive” nor lack of it mean non
destructive either. The bang sign means “the bang version is more
dangerous than its non bang counterpart; handle with care”.

Since Array#delete doesn’t have a less-dangerous counterpart, there is no need for the exclamation.