I know this is a basic question, but I couldn't find an answer.
Why use it? if you write a function or a method that's using it, when you remove it the code will still work perfectly, 100% as without it. …
I want a regular expression to check that
a password must be eight characters including one uppercase letter, one special character and alphanumeric characters.
And here is my validation expression which is for eight characters including one uppercase letter, one …