From: Ralf Mueller <ralf.mueller@...>
Date: 2012-04-13T17:00:06+09:00
Subject: Re: How to test if array element exists?

On 04/13/2012 09:53 AM, Jan E. wrote:
> Hi,
>
> If you access a non-existing index, you get nil. That is, your
> expression [array[4]] evaluates to [nil], which is not empty (but has
> exactly one element).
>
> The only way to test for existence is to check the length of the array:
>
> if 4>= array.length
>    puts 'no index 4'
> end
>
what about this
?> array = [0,1,2,3]
=> [0, 1, 2, 3]
 >> array[4]
=> nil
 >> array[4].nil?
=> true
 >> array[444].nil?
=> true
 >> array[2].nil?
=> false
 >>