How to cleanly verify if the user input is an integer in Ruby?

Question

I have a piece of code where I ask the user to input a number as an answer to my question. I can do to_i but tricky/garbage inputs would escape through to

Answer 1

Use input_string.to_i.to_s == input_string to verify whether the input_string is an integer or not without regex.

> input_string = "11a12"
> input_string.to_i.to_s == input_string
=> false
> input_string = "11"
> input_string.to_i.to_s == input_string
=> true
> input_string = "11.5"
> input_string.to_i.to_s == input_string
=> false