Den 16.12.2010 14:48, skrev flebber:
> HI
>
> doing the pharo tutorial and I wanted to know how pharo viewed the dynamic
> array at index 3(seems smalltalk starts at 1 not 0)
>
> >From the xample simple enough
> { (2+3) . (6*6) . 'hello', ' Stef'} size. 3
>
> from the strings example we found index by
>
> 'ProfStef' at: 1. $P
>
> so I thought { (2+3) . (6*6) . 'hello', ' Stef'} at 3. would let me know
> what the array was evaluated to after execution but it doesn't. Is it
> confused because it doesn't know whether I want the third array element or
> the third character?
>
> Led me to wonder the correct way if doing this, so that I could evaluate
> array 1 * 2.
>
> { (2+3) . (6*6) . 'hello', ' Stef'} at 1 * at 2. 180
>
>
> Cheers
What do you mean?
The dynamic array is created with three elements,
5 (2+3) at index 1,
36 (6*6) at index 2, and
'hello Stef' ('hello', ' Stef') at index 3.
at: 3 thus returns the string.
at 3 is invalid, as it is basically 2 method calls, array does not
understand a message called #at, and #3 is an invalid selector anyways.
For your second expression, writing
({ (2+3) . (6*6) . 'hello', ' Stef'} at: 1) * (at: 2) would not work,
as you're missing the receiver for the second at: call.
you'd need to do something like:
array := { (2+3) . (6*6) . 'hello', ' Stef'}.
(array at: 1) * (array at: 2). 180
Cheers,
Henry
