ruby-core

Issue #9970 has been updated by shyouhei (Shyouhei Urabe).


This issue has no move so far.  I think you need to start discussing about transform_keys if you want that.  It has one problem though; what happens when the transformed keys conflict is not intuitive.  Is that an exception? Or the latter wins?

```ruby
{ x: 1, y: 2 }.transform_keys {|*| :same_key } # should what happen?
```

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Feature #9970: Add `Hash#map_keys` and `Hash#map_values`
https://bugs.ruby-lang.org/issues/9970#change-64875

* Author: seantheprogrammer (Sean Griffin)
* Status: Open
* Priority: Normal
* Assignee: nobu (Nobuyoshi Nakada)
* Target version: 
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These methods simplify two common patterns when working with hashes, and transforming the data.

Without `map_keys`:

`Hash[{ a: 1, b: 2 }.map { |key, value| [key.to_s, value] }]`

With `map_keys`:

`{ a: 1, b: 2 }.map_keys(&:to_s)`

Without `map_values`:

`Hash[{ a: '1', b: '2' }.map { |key, value| [key, value.to_i] }]`

With `map_values`:

`{ a: '1', b: '2' }.map_values(&:to_i)`

The patch, with tests, is attached.

---Files--------------------------------
hash-map-keys-and-map-values.diff (5.79 KB)


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