How to get the selected item from Listbox and convert it to int?

[Jionni]

Hey wuf,

this help me a lot, you are amazing... But there is something I don't get yet.

How can I use the variable b for further coding? Ok, I can print out the result by pressig the ENTER-button, thats really nice and useful. But how can I assign the variable b, for example, to variable z, or taking the value of b and use it for another function.
You know what I mean? I want to use the value of b in another part of the code...