Issue #15831 has been updated by nobu (Nobuyoshi Nakada).


Why `Array#extract` has no argument but takes a block, while `Hash` and `ENV` are opposite?

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Feature #15831: Add `Array#extract`, `Hash#extract`, and `ENV::extract`
https://bugs.ruby-lang.org/issues/15831#change-78000

* Author: bogdanvlviv (Bogdan Denkovych)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
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## Add `Array#extract`

The method removes and returns the elements for which the block returns a true value.
If no block is given, an Enumerator is returned instead.

```ruby
numbers = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
odd_numbers = numbers.extract { |number| number.odd? } # => [1, 3, 5, 7, 9]
numbers # => [0, 2, 4, 6, 8]
```

This method was added to Active Support as `extract!` in https://github.com/rails/rails/pull/33137

In this post, you can find use cases of this method
https://bogdanvlviv.com/posts/ruby/rails/array-extract-to-activesupport-6-0.html


## Add `Hash#extract`

The method removes and returns the key/value pairs matching the given keys.

```ruby
h = {a: 100, b: 200, c: 300}
h.extract(:a) # => {:a=>100}
h # => {:b=>200, :c=>300}
h.extract(:b, :c, :d) # => {:b=>200, :c=>300}
h # => {}
```

This method was added to Active Support as `extract!` in 2009, see
https://github.com/rails/rails/commit/8dcf91ca113579646e95b0fd7a864dfb6512a53b

## Add `ENV::extract`

The method removes and returns the key/value pairs matching the given keys.

```ruby
ENV.extract("PORT", "RAILS_ENV") # => {"PORT"=>"3000", "RAILS_ENV"=>"development"}
```

Pull Request: https://github.com/ruby/ruby/pull/2171



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