Module: Enumerable

Defined in:
lib/active_object/enumerable.rb

Instance Method Summary collapse

Instance Method Details

#cluster(&block) ⇒ Object 



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# File 'lib/active_object/enumerable.rb', line 3

def cluster(&block)
  result = []
  each do |element|
    if result.last && (yield(result.last.last) == yield(element))
      result.last << element
    else
      result << [element]
    end
  end
  result
end

#difference(identity = 0, &block) ⇒ Object 



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# File 'lib/active_object/enumerable.rb', line 15

def difference(identity=0, &block)
  if block_given?
    map(&block).difference(identity)
  else
    inject { |d, v| d - v } || identity
  end
end

#divisible(identity = 0, &block) ⇒ Object 



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# File 'lib/active_object/enumerable.rb', line 23

def divisible(identity=0, &block)
  if block_given?
    map(&block).divisible(identity)
  else
    inject { |d, v| d / v } || identity
  end
end

#drop_last(n) ⇒ Object 



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# File 'lib/active_object/enumerable.rb', line 31

def drop_last(n)
  collection_length = to_a.length

  return(self) if n > collection_length

  self[0...(collection_length - n)]
end

#drop_last_if ⇒ Object 



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# File 'lib/active_object/enumerable.rb', line 39

def drop_last_if
  return(to_enum(:drop_last_if)) unless block_given?

  result = []
  dropping = true
  reverse_each do |value|
    result.unshift(value) unless dropping &&= yield(value)
  end
  result
end

#exactly?(n) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_object/enumerable.rb', line 50

def exactly?(n)
  found_count = 0
  block_given? ? each { |*o| found_count += 1 if yield(*o) } : each { |o| found_count += 1 if o }
  (found_count > n) ? false : n == found_count
end

#exclude?(object) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_object/enumerable.rb', line 56

def exclude?(object)
  !include?(object)
end

#expand ⇒ Object 



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# File 'lib/active_object/enumerable.rb', line 60

def expand
  map { |n| n.is_a?(Enumerable) ? n.expand : n }
end

#exponential(identity = 0, &block) ⇒ Object 



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# File 'lib/active_object/enumerable.rb', line 64

def exponential(identity=0, &block)
  if block_given?
    map(&block).exponential(identity)
  else
    inject { |d, v| d ** v } || identity
  end
end

#frequencies ⇒ Object 



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# File 'lib/active_object/enumerable.rb', line 72

def frequencies
  each_with_object(Hash.new(0)) { |e, a| a[e] += 1 }
end

#incase?(object) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_object/enumerable.rb', line 76

def incase?(object)
  any? { |x| object === x }
end

#many? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_object/enumerable.rb', line 80

def many?
  found_count = 0
  if block_given?
    any? do |v|
      found_count += 1 if yield v
      found_count > 1
    end
  else
    any? { (found_count += 1) > 1 }
  end
end

#max(identity = 0) ⇒ Object 



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# File 'lib/active_object/enumerable.rb', line 92

def max(identity=0)
  (length rescue count) > 0 ? sort.last : identity
end

#mean(identity = 0) ⇒ Object Also known as: average 



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# File 'lib/active_object/enumerable.rb', line 100

def mean(identity=0)
  return(identity) unless length > 0

  collection_length = length
  sum.to_f / collection_length.to_f
end

#median(identity = 0) ⇒ Object 



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# File 'lib/active_object/enumerable.rb', line 109

def median(identity=0)
  collection_length = length.to_f
  collection_sorted = sort

  return(identity) unless collection_length > 0.0

  if (collection_length % 2).zero?
    (collection_sorted[(collection_length / 2.0) -1.0] + collection_sorted[collection_length / 2.0]) / 2.0
  else
    collection_sorted[collection_length / 2.0]
  end
end

#min(identity = 0) ⇒ Object 



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# File 'lib/active_object/enumerable.rb', line 96

def min(identity=0)
  (length rescue count) > 0 ? sort.first : identity
end

#mode(identity = 0) ⇒ Object 



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# File 'lib/active_object/enumerable.rb', line 122

def mode(identity=0)
  return(identity) unless length > 0

  frequency_distribution = inject(Hash.new(0)) { |h, v| h[v] += 1; h }
  frequency_top_two = frequency_distribution.sort { |k, v| v[1] <=> k[1] }.take(2)

  if frequency_top_two.length == 1
    frequency_top_two.first.first
  elsif frequency_top_two.first.last == frequency_top_two.last.last
    nil
  else
    frequency_top_two.first.first
  end
end

#multiple(identity = 0, &block) ⇒ Object 



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# File 'lib/active_object/enumerable.rb', line 137

def multiple(identity=0, &block)
  if block_given?
    map(&block).multiple(identity)
  else
    inject { |d, v| d * v } || identity
  end
end

#range(identity = 0) ⇒ Object 



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# File 'lib/active_object/enumerable.rb', line 145

def range(identity=0)
  return(identity) unless length > 0

  collection_sorted = sort
  collection_sorted.last - collection_sorted.first
end

#several? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_object/enumerable.rb', line 152

def several?
  found_count = 0
  block_given? ? each { |*o| found_count += 1 if yield(*o) } : each { |o| found_count += 1 if o }
  (found_count > 1) ? true : false
end

#standard_deviation(identity = 0) ⇒ Object 



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# File 'lib/active_object/enumerable.rb', line 158

def standard_deviation(identity=0)
  return(identity) if length < 2

  Math.sqrt(variance)
end

#sum(identity = 0, &block) ⇒ Object 



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# File 'lib/active_object/enumerable.rb', line 164

def sum(identity=0, &block)
  if block_given?
    map(&block).sum(identity)
  else
    inject { |s, v| s + v } || identity
  end
end

#take_last(n) ⇒ Object 



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# File 'lib/active_object/enumerable.rb', line 172

def take_last(n)
  collection_length = to_a.length

  return(self) if n > collection_length

  self[(collection_length - n)..-1]
end

#take_last_if ⇒ Object 



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# File 'lib/active_object/enumerable.rb', line 180

def take_last_if
  return(to_enum(:take_last_if)) unless block_given?

  result = []
  reverse_each { |e| yield(e) ? result.unshift(e) : break }
  result
end

#variance(identity = 0) ⇒ Object 



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# File 'lib/active_object/enumerable.rb', line 188

def variance(identity=0)
  collection_length = length

  return(identity) if collection_length <= 1

  sum = inject(0.0) { |s,v| s + (v - mean) ** 2.0 }
  sum.to_f / (collection_length.to_f - 1.0)
end