From: duerst@... Date: 2020-09-27T07:52:32+00:00 Subject: [ruby-core:100184] [Ruby master Feature#15831] Add `Array#extract`, `Hash#extract`, and `ENV.extract` Issue #15831 has been updated by duerst (Martin D�rst). I'm not exactly at ease with the fact that the proposed methods both change the receiver and return a result. But if the names have an '!' at the end, it might be okay. ---------------------------------------- Feature #15831: Add `Array#extract`, `Hash#extract`, and `ENV.extract` https://bugs.ruby-lang.org/issues/15831#change-87756 * Author: bogdanvlviv (Bogdan Denkovych) * Status: Rejected * Priority: Normal ---------------------------------------- ## 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 for which the block evaluates to +true+. If no block is given, an Enumerator is returned instead. ```ruby h = {a: 100, b: 200, c: 300} h.extract {|k, v| v > 150} # => {:b=>200, :c=>300} h # => {:a=>100} ``` Note that there is method `extract!` in Active Support that was added in 2009, see https://github.com/rails/rails/commit/8dcf91ca113579646e95b0fd7a864dfb6512a53b But I think we should upstream `extract!` to Ruby as `slice!`. ## Add `ENV.extract` The method removes and returns the key/value pairs for which the block evaluates to +true+. If no block is given, an Enumerator is returned instead. ```ruby ENV.extract {|k, v| k == "PORT"} # => {"PORT"=>"3000"} ``` Pull Request: https://github.com/ruby/ruby/pull/2171 Patch: https://patch-diff.githubusercontent.com/raw/ruby/ruby/pull/2171.patch -- https://bugs.ruby-lang.org/ Unsubscribe: