Array#at(selector,...)

ruby-talk
1

Is there good reason to have two different methods for this?

  array.at(index)
  array.values_at(selector,... )

And then

  array.delete_at(index)

Can't this take selector instead?

I imagine there are other methods related as well.

T.

2

Is there good reason to have two different methods for this?

  array.at(index)
  array.values_at(selector,... )

To help answer my own question. A problem arises with output on single element
results:

  a = [1,2,3,4,5]
  a.at(0) #=> 1
  a.values_at(0) #=> [1]

The only alternatives I see for unification would be to have #at take an Array
or ignore nil:

  a.at([0]) #=> [1]
  a.at(0,nil) #=> [1]

But barring that (or a better solution), my REAL PROBLEM boils down to how
best to implement a method related to this but that doesn't have the same
difficulty. For example (completely contrived):

  class Array
    def part(n=nil)
      if n
        values_at(0..n)
      else
        at(0)
      end
    end
  end

Is it better to have two methods instead --an #at_part and a #values_at_part?
Personally I prefer the single method but that seems to go against the
at/values_at grain. So that's why I'm inquiring into it.

And then

  array.delete_at(index)

Can't this take selector instead?

This still seems reasonable.

T.

···

On Tuesday 14 December 2004 10:17 am, trans. (T. Onoma) wrote:

3

Hi,

Is there good reason to have two different methods for this?

array.at(index)
array.values_at(selector,... )

Return value, the latter returns an array of specified values.

And then

array.delete_at(index)

Can't this take selector instead?

The change would cause incompatibility in return values.

              matz.

···

In message "Re: Array#at(selector,...)" on Wed, 15 Dec 2004 00:17:25 +0900, "trans. (T. Onoma)" <transami@runbox.com> writes:

4

Hi,

···

On Tuesday 14 December 2004 07:05 pm, Yukihiro Matsumoto wrote:

In message "Re: Array#at(selector,...)" > > on Wed, 15 Dec 2004 00:17:25 +0900, "trans. (T. Onoma)" <transami@runbox.com> writes:
>Is there good reason to have two different methods for this?
>
> array.at(index)
> array.values_at(selector,... )

Return value, the latter returns an array of specified values.

>And then
>
> array.delete_at(index)
>
>Can't this take selector instead?

The change would cause incompatibility in return values.

Ah I see, same difficulty. Thank you.

So then, I am under the impression that the two method approach is best --a
#delete_values_at for instance.

T.

5

Hi,

···

In message "Re: Array#at(selector,...)" on Wed, 15 Dec 2004 10:02:48 +0900, "trans. (T. Onoma)" <transami@runbox.com> writes:

So then, I am under the impression that the two method approach is best --a
#delete_values_at for instance.

If you want both functionality.

              matz.