[ruby-core:101145] [Ruby master Feature#8421] add Enumerable#find_map and Enumerable#find_all_map

[fluff@lukeswart.net]

Issue #8421 has been updated by modulitos (Lucas Swart).


matz (Yukihiro Matsumoto) wrote in #note-1:
> Could you tell me a concrete use-case of your find_map and find_all_map?
> Usually a block for find/find_all gives boolean so that I personally have never wanted the return value from it.
> 
> Matz.

In Ruby 2.7, I think we can use `enumerable.lazy.filter_map{..}.first` as an equivalent for `.find_map{..}`

matz (Yukihiro Matsumoto) wrote in #note-1:
> Could you tell me a concrete use-case of your find_map and find_all_map?
> Usually a block for find/find_all gives boolean so that I personally have never wanted the return value from it.
> 
> Matz.



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Feature #8421: add Enumerable#find_map and Enumerable#find_all_map
https://bugs.ruby-lang.org/issues/8421#change-88830

* Author: Hanmac (Hans Mackowiak)
* Status: Feedback
* Priority: Normal
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currently if you have an Enumerable and you want to return the return value of #find you need eigther:
  (o = enum.find(block) && block.call(o)) || nil
or
  enum.inject(nil) {|ret,el| ret || block.call(el)}

neigher of them may be better than an directly maked method

same for #find_all_map
  enum.lazy.map(&:block).find_all{|el| el}

it may work but it is not so good



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