[ruby-core:96364] [Ruby master Misc#16436] hash missing #last method, make it not so consistent (it has first)
From:
vil963@...
Date:
2019-12-20 03:18:30 UTC
List:
ruby-core #96364
Issue #16436 has been updated by zw963 (Wei Zheng).
zw963 (Wei Zheng) wrote:
> ``` ruby
> (pry):main(0)> h = {x:1, y:2, z:3}
> {
> :x => 1,
> :y => 2,
> :z => 3
> }
> (pry):main(0)> h.first
> [
> :x,
> 1
> ]
> (pry):main(0)> h.first.first
> :x
> (pry):main(0)> h.first.last
> 1
> ```
>
> last method not exist.
>
> ```ruby
> (pry):main(0)> h.last
>
> Exception: NoMethodError: undefined method `last' for {:x=>1, :y=>2, :z=>3}:Hash
> ```
>
> We have to use #to_a to make last working.
>
> ```ruby
> (pry):main(0)> h.to_a.last
> [
> :z,
> 3
> ]
>
> (pry):main(0)> h.to_a.last.first
> :z
> (pry):main(0)> h.to_a.last.last
> 3
> ```
sawa (Tsuyoshi Sawada) wrote:
> What is this issue? Is it just a note to everyone, or are you claiming this to be a bug, or is it a feature request?
Sorry, this issue not a bug, i knew Hash#first come from Enumerable, the reason i issue it is: i love ruby language, use it days and days,
when encountering some inconsistencies things, i expect to give some feedback, and what i thought.
So, for this issue, the question is:
why Array include Enumerable module, and implement Array#first Array#last method, if we should do same things for Hash?
make this language more elegant?
----------------------------------------
Misc #16436: hash missing #last method, make it not so consistent (it has first)
https://bugs.ruby-lang.org/issues/16436#change-83274
* Author: zw963 (Wei Zheng)
* Status: Open
* Priority: Normal
* Assignee:
----------------------------------------
``` ruby
(pry):main(0)> h = {x:1, y:2, z:3}
{
:x => 1,
:y => 2,
:z => 3
}
(pry):main(0)> h.first
[
:x,
1
]
(pry):main(0)> h.first.first
:x
(pry):main(0)> h.first.last
1
```
last method not exist.
```ruby
(pry):main(0)> h.last
Exception: NoMethodError: undefined method `last' for {:x=>1, :y=>2, :z=>3}:Hash
```
We have to use #to_a to make last working.
```ruby
(pry):main(0)> h.to_a.last
[
:z,
3
]
(pry):main(0)> h.to_a.last.first
:z
(pry):main(0)> h.to_a.last.last
3
```
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