Regex to test character length of a string

Question

How do I test to see the length of a string using regex?

For example, how do i match a string if it contains only 1 character?

Answer 1

^.$

But most frameworks include methods that will return string length, which you should use instead of regex for this.

Answer 2

Anchor to the start and end of string and match one character. In many languages:

^.{1}$

In Ruby's Regex:

\A.{1}\z