Regular expression to match exact number of characters?

Question

I need a regular expression that will match any three uppercase letters, so AAA or ABC or DKE. It can\'t match four or more though, like AAAA or ABCDEF or aBBB.

My s

Answer 1

What you have is correct, but this is more consice:

^[A-Z]{3}$

Answer 2

Your solution is correct, but there is some redundancy in your regex.
The similar result can also be obtained from the following regex:

^([A-Z]{3})$

The {3} indicates that the [A-Z] must appear exactly 3 times.