From: Sebastian Hungerecker <sepp2k@...>
Date: 2009-01-12T07:34:12+09:00
Subject: Re: Checking if input == Integer/String?

Ulrich Holtzhausen wrote:
> puts "What is your favourite number?"
> num = gets.to_i
> if num != Integer
>   puts "Please type a number"
> else
>   better = num + 1
>   puts "Hah! #{num} is pathetic! #{better} is a much better number!!!"
> end
>
> Somewhere along the line there's a mistake however, but I take it you
> guru's can see what I'm trying to do here?
>
> How can I check if the variable 'num' is an integer and if not, ask the
> user to re-input with an integer?

to_i always returns an Integer (if the string isn't a valid number, it just 
returns 0). If you don't want that you can use Integer(str) which raises an 
exeption if the string is not a valid number.
Also note that 4 == Integer is false. Only Integer is == Integer.
num.is_a? Integer would work, but as I said, to_i always returns an Integer,
so that would always be true.

HTH,
Sebastian
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