Feature #19987: add sample method to Range

• Status: Feedback
• Assignee: -
• Target version: -

[[e-mail] (Andras Horvath)]

Dear Devs, I'd like to suggest a change. Since the following works:

(1..99).first(5)

Therefore this one could be logical and useful to work:

(1..99).sample(5)

Thanks,
Andras

[ufuk (Ufuk Kayserilioglu)]

The first call works because Range is an Enumerable, and since getting the first element is an act of enumeration. On the other hand, sample needs to know the full list to do what it is doing, so can't be seen as an act of enumeration.

For example, first would work with an unbounded enumerable, but there is no way sample could:

(1..).first(5)
# => [1, 2, 3, 4, 5]

Sounds logical, thank you.

Andras

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[rubyFeedback (robert heiler)]

I think conceptually .first() is not the same as .sample(). At the least when I read
it, I would assume that .first() yields the first five elements (if the argument is
5), whereas .sample() should probably return 5 random elements. Not sure if others
read it the same way, but that was my initial impression.

[nobu (Nobuyoshi Nakada)]

• Status changed from Open to Feedback

Even if limited to bound Range, we can't enumerate all possible elements in Float.
As in the first proposal, it would make sense only for Integer ranges.

May we close this?

[nobu (Nobuyoshi Nakada)]

Maybe what you want is Random#rand with a Range?

r = Random.new
5.times.map {r.rand(0..99)} #=> [83, 63, 43, 70, 90]