How can I get the characters between 2 other characters?

Question

I have a string which at some point contains the set of characters in the following format [123].

What I would like to do is get the characters between

Answer 1

Dim s As String = "nav[1]=root"
dim result as String = s.Substring(s.IndexOf("[") + 1, s.IndexOf("]", s.IndexOf("[")) - s.IndexOf("[") - 1)