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 = "foo [123]=ro bar"
Dim i As Integer = s.IndexOf("[")
Dim f As String = s.Substring(i + 1, s.IndexOf("]", i + 1) - i - 1)