[ruby-core:92014] [Ruby trunk Feature#15730] Add map_with_index method

Issue #15730 has been updated by jeremyevans0 (Jeremy Evans).


jzakiya (Jabari Zakiya) wrote:
> I was converting some Ruby code to Crystal on Rosetta Code and came across this Ruby snippet,
> 
> ```
> arry.each_with_index.map{ |x,y| ......}
> ```
> where ``arry`` is an array of integers.
> 
> This wouldn't convert directly into Crystal (wouldn't compile).
> Looking at their ``enumerables`` methods they have ``map_with_index``, and that works.
> 
> ```
> arry.map_with_index{ |x,y| ......}
> ```
> 
> I don't know how frequently in Ruby this method combination exits, but I suspect it's somewhat common.
> I think this method makes a whole lot of logical sense, would optimize the concept, and makes reading code easier.
> Anyway, thanks for any consideration.

Enumerator#with_index already exists:

```ruby
 [1,3,5].map.with_index{ |x, i| (x+i)**2}
=> [1, 16, 49]
```

I believe the reason Enumerable#each_with_index is a separate method is because it was added before Enumerator#with_index.  However, I don't think it makes sense to add more *_with_index methods.

----------------------------------------
Feature #15730: Add map_with_index method
https://bugs.ruby-lang.org/issues/15730#change-77341

* Author: jzakiya (Jabari Zakiya)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
----------------------------------------
I was converting some Ruby code to Crystal on Rosetta Code and came across this Ruby snippet,

```
arry.each_with_index.map{ |x,y| ......}
```
where ``arry`` is an array of integers.

This wouldn't convert directly into Crystal (wouldn't compile).
Looking at their ``enumerables`` methods they have ``map_with_index``, and that works.

```
arry.map_with_index{ |x,y| ......}
```

I don't know how frequently in Ruby this method combination exits, but I suspect it's somewhat common.
I think this method makes a whole lot of logical sense, would optimize the concept, and makes reading code easier.
Anyway, thanks for any consideration.



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