Implement #map#to_h vs #each_with_object #93

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1. kbrock commented on Apr 27, 2018

   

   kbrock

   on Apr 27, 2018

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   just create a pr for this or close?
2. mateusdeap commented on Nov 3, 2022

   

   mateusdeap

   on Nov 3, 2022

   Last edited by mateusdeap

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   So... I ran this benchmark using ruby 3 and there really wasn't much of a difference. Here's the script I ran:

   require 'benchmark/ips'
   
   HASH = { a: 2, b: 3 }
   N = 1_000_000
   
   def slow
     HASH.map { |k, v| [k, v + 3] }.to_h
   end
   
   def fast
     HASH.each_with_object({}) { |(k, v), a| a[k] = v + 3 }
   end
   
   Benchmark.ips do |x|
     x.report('Enumerable#map#to_h') { N.times { slow } }
     x.report('Enumerable#each_with_object') { N.times { fast } }
     x.compare!
   end

   And here's the result:

   ruby -v code/enumerable/map-to-h-vs-each-with-object.rb                                                                                                              20:34:33
   ruby 3.0.2p107 (2021-07-07 revision 0db68f0233) [x86_64-darwin20]
   Warming up --------------------------------------
    Enumerable#map#to_h     1.000  i/100ms
   Enumerable#each_with_object
                            1.000  i/100ms
   Calculating -------------------------------------
    Enumerable#map#to_h      1.480  (± 0.0%) i/s -      8.000  in   5.406527s
   Enumerable#each_with_object
                             1.584  (± 0.0%) i/s -      8.000  in   5.049983s
   
   Comparison:
   Enumerable#each_with_object:        1.6 i/s
    Enumerable#map#to_h:        1.5 i/s - 1.07x  (± 0.00) slower

   So, any sense in still having this?