From: Shugo Maeda <shugo@...>
Date: 2015-12-18T13:31:09+09:00
Subject: [ruby-core:72354] Re: [Ruby trunk - Feature #11797] [Open] `Enumerator#with_object` with multiple objects

Hello,

I've removed his address from ruby-core and ruby-talk.

2015-12-18 13:27 GMT+09:00 Joseph Jones <joeyi5216@gmail.com>:
> Joseph Jones liked your message with Boxer.
>
>
> On December 9, 2015 at 09:15:54 MST, sawadatsuyoshi@gmail.com wrote:
>
> Issue #11797 has been reported by Tsuyoshi Sawada.
>
> ----------------------------------------
> Feature #11797: `Enumerator#with_object` with multiple objects
> https://bugs.ruby-lang.org/issues/11797
>
> * Author: Tsuyoshi Sawada
> * Status: Open
> * Priority: Normal
> * Assignee:
> ----------------------------------------
> Sometimes, when working with `Enumerator#with_object`, I want to keep some
> additional temporary objects besides the one to return. A use case is as
> follows (I got this from this StackOverflow question:
> http://stackoverflow.com/questions/3418123). Suppose I have an enumerator
> created from an array:
>
> e = ["a", "b", "c", "c", "a", "c"].to_enum
>
> and want to get an array of its repeated elements in the order they are
> repeated (i.e., appears for the second time):
>
> # => ["c", "a"]
>
> I can do it using `Enumerator#with_object` like this:
>
> e.to_enum.with_object([{}, []]){|c, (h, a)| h[c] ? a.push(c) : h.store(c,
> true)}.last.uniq
>
> Here, I am getting the array referred to as `a` in the block, but besides
> that, I am using a temporal hash `h`. I thought it would be nice if
> `Enumerator#with_object` accepts one or more objects, pass them individually
> as block arguments, and returns only the last argument so that I can do
> this:
>
> e.to_enum.with_object({}, []){|c, h, a| h[c] ? a.push(c) : h.store(c,
> true)}.uniq
>
>
>
>
> --
> https://bugs.ruby-lang.org/



-- 
Shugo Maeda