Class: Array

Inherits:
Object show all
Defined in:
lib/kitchensink/patches/array.rb,
lib/kitchensink/patches/array.rb,
lib/kitchensink/patches/array.rb,
lib/kitchensink/patches/array.rb,
lib/kitchensink/patches/array.rb,
lib/kitchensink/patches/array.rb,
lib/kitchensink/patches/array.rb

Instance Method Summary collapse

Instance Method Details

#hash_by(attribute) ⇒ Object

Construct a hash of objects, keyed by some object attribute.

Original idea and code by Brian Dainton. Taken from his blog, The Budding Rubyist. buddingrubyist.wordpress.com/2008/02/05/why-i-like-to-inject/



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# File 'lib/kitchensink/patches/array.rb', line 7

def hash_by(attribute)
  inject({}) do |results, obj|
    results[obj.send(attribute)] = obj
    results
  end
end

#product ⇒ Object

Multiplies all elements of an array together:

  • [2,3,4].product => 24

  • [2.0, 3.0, 4.0].product => 24.0

  • [“NO”, 3, 2].product => “NONONONONONO”



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# File 'lib/kitchensink/patches/array.rb', line 22

def product
  inject {|product,element| product*element}
end

#rand_index ⇒ Object

returns a random index from this array



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# File 'lib/kitchensink/patches/array.rb', line 31

def rand_index
  rand(size)
end

#rand_value ⇒ Object

returns a random value from this array



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# File 'lib/kitchensink/patches/array.rb', line 40

def rand_value
  self[rand(size)]
end

#shuffle ⇒ Object

Returns an array with its elements shuffled. Uses algorithm from Ruby Cookbook 4.10



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# File 'lib/kitchensink/patches/array.rb', line 74

def shuffle
  self.dup.shuffle!
end

#shuffle! ⇒ Object

Returns an array with its elements shuffled. Uses algorithm from Ruby Cookbook 4.10



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# File 'lib/kitchensink/patches/array.rb', line 63

def shuffle!  
  each_index do |i| 
    j = rand(length-i) + i
    self[j], self[i] = self[i], self[j]  
  end
end

#sum ⇒ Object

Adds all elements of an array together:

  • [1,2,3].sum => 6

  • [1.0, 2.0, 3.0].sum => 6.0

  • %wb c.sum => “abc”

  • Vector, Vector, Vector].sum => Vector[1,2,3


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# File 'lib/kitchensink/patches/array.rb', line 53

def sum
  inject {|sum,element| sum+element}
end