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bogdanvlviv Refactor `Array#extract!`
Avoid allocating the second array by using `Array#reject!` instead of
`Enumerable#partition` in `Array#extract!`.

There are benchmarks in order to ensure that the changes speed up the method:
```
begin
  require "bundler/inline"
rescue LoadError => e
  $stderr.puts "Bundler version 1.10 or later is required. Please update
your Bundler"
  raise e
end

class Array
  def extract_v1!(&block)
    unless block_given?
      to_enum(:extract!) { size }
    else
      extracted_elements, other_elements = partition(&block)

      replace(other_elements)

      extracted_elements
    end
  end

  def extract_v2!
    return to_enum(:extract!) { size } unless block_given?

    extracted_elements = []

    reject! do |element|
      extracted_elements << element if yield(element)
    end

    extracted_elements
  end
end

gemfile(true) do
  source "https://rubygems.org"

  gem "benchmark-ips"
end

arrays_for_partition = Array.new(1000) { (0..10000).to_a }
arrays_for_extract_v1 = Array.new(1000) { (0..10000).to_a }
arrays_for_extract_v2 = Array.new(1000) { (0..10000).to_a }

Benchmark.ips do |x|
  x.report("Array#partition")  do
    arrays_for_partition.each do |numbers|
      odd_numbers, numbers = numbers.partition { |number| number.odd? }
      numbers
    end
  end

  x.report("Array#extract_v1!")  do
    arrays_for_extract_v1.each do |numbers|
      odd_numbers = numbers.extract_v1! { |number| number.odd? }
      numbers
    end
  end

  x.report("Array#extract_v2!")  do
    arrays_for_extract_v2.each do |numbers|
      odd_numbers = numbers.extract_v2! { |number| number.odd? }
      numbers
    end
  end

  x.compare!
end
```

The result of the benchmarks:

```
ruby -v
ruby 2.5.1p57 (2018-03-29 revision 63029) [x86_64-linux]
```

```
Fetching gem metadata from https://rubygems.org/.
Resolving dependencies...
Using benchmark-ips 2.7.2
Using bundler 1.16.1
Warming up --------------------------------------
     Array#partition     1.000  i/100ms
   Array#extract_v1!     1.000  i/100ms
   Array#extract_v2!     1.000  i/100ms
Calculating -------------------------------------
     Array#partition      1.390  (± 0.0%) i/s -      7.000  in   5.044843s
   Array#extract_v1!      2.781  (± 0.0%) i/s -     14.000  in   5.050589s
   Array#extract_v2!      3.151  (± 0.0%) i/s -     16.000  in   5.080608s

Comparison:
   Array#extract_v2!:        3.2 i/s
   Array#extract_v1!:        2.8 i/s - 1.13x  slower
     Array#partition:        1.4 i/s - 2.27x  slower
```

Avoid `unless`/`else` in favour of an early return.
The double-negative of that `else` can be confusing,
even though the code layout is nearly the same.
Also using of early return would improve `git diff`
if we needed to change this method.
Latest commit b71abb3 Jun 15, 2018

README.rdoc

Active Support – Utility classes and Ruby extensions from Rails

Active Support is a collection of utility classes and standard library extensions that were found useful for the Rails framework. These additions reside in this package so they can be loaded as needed in Ruby projects outside of Rails.

Download and installation

The latest version of Active Support can be installed with RubyGems:

$ gem install activesupport

Source code can be downloaded as part of the Rails project on GitHub:

License

Active Support is released under the MIT license:

Support

API documentation is at:

Bug reports for the Ruby on Rails project can be filed here:

Feature requests should be discussed on the rails-core mailing list here: