Ruby Idioms

Transcript

1. RUBY & RUBY ON RAILS
   IDIOMS
   

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2. A word on style
   

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3. - Soft tabs, two space indent
   - Lines shorter than 80 characters
   - No spaces after [( and before )]
   - Methods: snake_case
   - Classes/Modules: CamelCase
   - Constants: SCREAMING_SNAKE_CASE
   - Space after commas: foo(a, b)
   

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4. “Idioms”
   

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5. if answer == 42
   # ...
   elsif foo == 'foo'
   # ...
   else
   # ...
   end
   

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6. if answer == 42 then # ...
   elsif foo == 'foo' then # ...
   else # ...
   end
   

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7. if answer == 42 then
   # ...
   elsif foo == 'foo' then
   # ...
   else
   # ...
   end
   

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8. if !correct
   # ...
   end
   

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9. unless correct
   # ...
   end
   

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10. unless correct
    # ...
    else
    # ...
    end
    

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11. unless correct
    single_line_of_something
    end
    

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12. single_line_of_something unless correct
    single_line_of_something if correct
    

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13. message = if correct
    "You are right!"
    else
    "Sorry, that's wrong."
    end
    

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14. if !flaky_value.nil?
    # ...
    end
    

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15. if flaky_value
    # ...
    end
    

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16. if env == :production or env == :development
    # ...
    end
    

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17. if [:production, :development].include?(env)
    # ...
    end
    

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18. String(123)
    

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19. 123.to_s
    

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20. 123.is_a? String
    

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21. 123.respond_to? :to_s
    

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22. def destroy_universe
    # ...
    end
    destroy_universe
    def destroy_planet(planet)
    # ...
    end
    destroy_planet(:mars)
    

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23. destroy_universe()
    

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24. def foo(arg1, arg2)
    # ...
    end
    foo 1, 2
    

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25. def foo(options, &block)
    # ...
    end
    foo {}
    

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26. def green?
    # ...
    end
    def destroy!
    # ...
    end
    

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27. def foo(name, options)
    # ...
    end
    foo('bar', {:something => 'else', :answer => 42})
    foo('bar', :something => 'else', :answer => 42)
    

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28. def foo
    # ... body
    return results
    end
    

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29. def foo(arg)
    return unless arg == 42
    # ... body
    end
    

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30. a, b = b, a
    

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31. a, b = [1, 2, 3]
    

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32. %w(helsinki oulu tampere)
    # => ["helsinki", "oulu", "tampere"]
    

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33. %i(helsinki oulu tampere)
    # => [:helsinki, :oulu, :tampere]
    

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34. %i|helsinki oulu tampere|
    %i-helsinki oulu tampere-
    

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35. the_number ||= complex_calculation
    

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36. list = []
    dictionary = {}
    

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37. class Store
    class << self
    def advanced_search
    # ...
    end
    end
    end
    

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38. Struct.new("Point", :x, :y)
    

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39. class Point < Struct.new(:x, :y)
    end
    origin = Point.new(0,0)
    

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40. Point = Struct.new(:x, :y) do
    def to_s
    "[#{x}, #{y}]"
    end
    end
    Point.new(0,0).to_s
    # => "[0, 0]"
    

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41. class Parent
    @@class_var = "parent"
    def self.print_class_var
    puts @@class_var
    end
    end
    class Child < Parent
    @@class_var = "child"
    end
    Parent.print_class_var
    # => "child"
    

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42. upcase_chars = []
    %w(a b c).each do |char|
    upcase_chars << char.upcase
    end
    Not so great
    

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43. %w(a b c).map do |char|
    char.upcase
    end
    Better
    

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44. %w(a b c).map { |char| char.upcase }
    Even better
    

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45. %w(a b c).map(&:upcase)
    Great
    

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46. Brand.first.stores.map(&:id)
    Brand.first.store_ids
    @active_brands.ids
    

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47. def make_it_bigga(string)
    string.upcase
    end
    %w(a b c).map(&method(:make_it_bigga))
    

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48. [1, 2, nil, 4].compact.reject(&:odd?).inject(&:+)
    # => 6
    

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49. {:foo => "bar", :baz => 42}.each do |key, value|
    puts "#{key}: #{value}"
    end
    # foo: bar
    # baz: 42
    # => {:foo=>"bar", :baz=>42}
    

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50. [[:foo, "bar"], [:baz, 42]].each do |(key, value)|
    puts "#{key}: #{value}"
    end
    # foo: bar
    # baz: 42
    # => {:foo=>"bar", :baz=>42}
    

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51. [[:foo, "bar"], [:baz, 42]].each do |(_, value)|
    puts value
    end
    # bar
    # 42
    # => [[:foo, "bar"], [:baz, 42]]
    

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52. name == ""
    name.length == 0
    name.empty?
    

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53. count == 0
    count.zero?
    

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54. dangerous rescue nil
    

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55. FOLLOW YOUR
    

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