Forum: Ruby firtst and only element of array (noob level)

Hello people,

Lets say i have
arr = [100]
and
i = 100

Now i do calculation:
i * arr[0] ==> 10000 # works ok
but
i * arr ==> Error

Why arr != arr[0] with only one element in the array?


And is there a way to 'free' the first and only object in arr?
As if it never belonged to an array, like 'i' ?

I know with a float or integer one can use:

a.to_s.to_i or a.to_s.to_f

but how about other objects?

Thanx for your thoughts!

Am 11.02.2013 13:27 schrieb "Ronnie Aa" <lists@ruby-forum.com>:
> but
> i * arr ==> Error
>
> Why arr != arr[0] with only one element in the array?

arr is the whole Array object and arr[0] is the first element of the 
array
(= 100) and these are not equal.

Thomas Preymesser wrote in post #1096273:
> Am 11.02.2013 13:27 schrieb "Ronnie Aa" <lists@ruby-forum.com>:
>> but
>> i * arr ==> Error
>>
>> Why arr != arr[0] with only one element in the array?
>
> arr is the whole Array object and arr[0] is the first element of the
> array
> (= 100) and these are not equal.

Yes but when the array contains only ONE element
there's no real need to indicate the position of that element.
So i want to use arr as if it was arr[0]. But that's no possible..

thnx for your answer

Subject: Re: firtst and only element of array (noob level)
  Date: lun 11 feb 13 10:43:27 +0900

Quoting Ronnie Aa (lists@ruby-forum.com):

> Yes but when the array contains only ONE element
> there's no real need to indicate the position of that element.
> So i want to use arr as if it was arr[0]. But that's no possible..

You have to think of the array as the chest of apples. When you have
only one apple left, the chest does not disappear. If it did, the
fact would generate a lot of confusion...

Carlo

Carlo E. Prelz wrote in post #1096281:
> Subject: Re: firtst and only element of array (noob level)
>   Date: lun 11 feb 13 10:43:27 +0900
>
> Quoting Ronnie Aa (lists@ruby-forum.com):
>
>> Yes but when the array contains only ONE element
>> there's no real need to indicate the position of that element.
>> So i want to use arr as if it was arr[0]. But that's no possible..
>
> You have to think of the array as the chest of apples. When you have
> only one apple left, the chest does not disappear. If it did, the
> fact would generate a lot of confusion...
>
> Carlo

Ok I see thnx

You could always run a check of the array and see how many items are in 
it, if
there is only one, then do something like:

array.first

that way you don't have to use [0].

Wayne


----- Original Message ----
From: Ronnie Aa <lists@ruby-forum.com>
To: ruby-talk ML <ruby-talk@ruby-lang.org>
Sent: Mon, February 11, 2013 8:14:24 AM
Subject: Re: firtst and only element of array (noob level)

Carlo E. Prelz wrote in post #1096281:
> only one apple left, the chest does not disappear. If it did, the
> fact would generate a lot of confusion...
>
> Carlo

Ok I see thnx

Wayne Brisette wrote in post #1096317:
> You could always run a check of the array and see how many items are in
> it, if
> there is only one, then do something like:
>
> array.first
>
> that way you don't have to use [0].
>
> Wayne
>

Hi Wayne,

Thnx for your suggestion