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@brodock Gabriel Mazetto 2 ɡ a b ɾ i ˈ ɛ w m a z ˈ ɛ t t u

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https://ruby-lang.org

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14 Highlights

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15 [experimental]

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irb(main):001:0> [1,2,3] in [a,b,c] irb(main):002:0> c => 3 16

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irb(main):001:0> [1,2,3] in [a,b,c] (irb):1: warning: Pattern matching is experimental, and the behavior may change in future versions of Ruby! => nil irb(main):002:0> c => 3 17

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GC.compact 20

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def something(args = {}) # ... end args = {a: 1, b: 2} something(args) 22

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def something(a:, b:) # ... end args = {a: 1, b: 2} something(args) 23

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def something(a:, b:) # ... end args = {a: 1, b: 2} something(args) warning: Using the last argument as keyword parameters is deprecated; maybe ** should be added to the call warning: The called method `something' is defined here 24

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def something(a:, b:) # ... end args = {a: 1, b: 2} something( **args) 25

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What is the ** syntax? 26

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def something( **args) # args => {a: 1, b: 2} end something(a: 1, b: 2) 27

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def something(a:, b:) # a = 1 # b = 2 end args = {a: 1, b: 2} something( **args) 28

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def something(*args) # args = [1, 2, 3] end something(1,2,3) 29

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def something(a, b, c) # a = 1 # b = 2 # c = 3 end args = [1,2,3] something(*args) 30

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def something(*args, **kwargs) # args = [1] # kwargs = {b: 2} end something(1, b: 2) 31

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def something(a, b:) end args = [1] kwargs = {b:2} something(*args, **kwargs) 32

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36 Lowlights

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38 # Ruby <= 2.6 10.times { |value| puts value } # Ruby 2.7 10.times { puts _1 }

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# Ruby 2.7 el = %W(a b c d e f a b a b c d a b) el.tally # => {"a" =>4, "b" =>4, "c" =>2, "d" =>2, "e" =>1, "f" =>1} 40

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# Ruby <= 2.6 V1 el.group_by { |v| v }.transform_values(&:size) 41

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# Ruby <= 2.6 V2 el.group_by { |v| v }.map { |k, v| [k, v.size] }.to_h 42

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# Ruby <= 2.6 V3 el.group_by { |v| v }.to_h { |k, v| [k, v.size] } 43

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# Ruby <= 2.6 V4 el.each_with_object(Hash.new(0)) { |v, h| h[v] += 1 } 44

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[1,2,3,4].intersection [2,3] # => [2, 3] 46

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enum = 1.upto(1_000) enum.filter_map { |i| i + 1 if i.even? } # => [3, 5, 7, 9, 11, 13, ...] 48

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CGI.escapeHTML(html) EscapeUtils.escape_html(html) 50

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Haml ::Helpers.html_escape(html) ERB ::Util.html_escape(html) String.gsub(/[&"'><]/, html_escape) Rack ::Utils.escape_html(html) 51

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52 One interesting story...

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New Japanese Era 54 Heisei Reiwa

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Unicode 12.1: 令和 U+32FF ㋿ (SQUARE ERA NAME REIWA) 55

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"\u4EE4\u548C" == "\u32FF".unicode_normalize(:nfkc) 56 令和 ㋿ 令和

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Unicode 12.1: New Emojis 57 ⚕⚕⚖ ✈

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58 The remaining question: Is Ruby 2.7 worth upgrading?

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