Module: Enumerable

Defined in:
lib/active_object/enumerable.rb

Instance Method Summary collapse

Instance Method Details

#cluster(&block) ⇒ Object

rubocop:disable Lint/UnusedMethodArgument



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# File 'lib/active_object/enumerable.rb', line 4

def cluster(&block)
  result = []
  each do |ele|
    last_res = result.last
    last_res && (yield(ele) == yield(last_res.last)) ? last_res << ele : result << [ele]
  end
  result
end

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

rubocop:enable Lint/UnusedMethodArgument



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# File 'lib/active_object/enumerable.rb', line 14

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

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



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# File 'lib/active_object/enumerable.rb', line 22

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

#drop_last(num) ⇒ Object 



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# File 'lib/active_object/enumerable.rb', line 30

def drop_last(num)
  collection_length = to_a.length
  return self if num > collection_length
  self[0...(collection_length - num)]
end

#drop_last_if ⇒ Object 



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# File 'lib/active_object/enumerable.rb', line 36

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

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

#exactly?(num) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_object/enumerable.rb', line 47

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

#exclude?(object) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_object/enumerable.rb', line 57

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

#expand ⇒ Object 



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# File 'lib/active_object/enumerable.rb', line 61

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

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



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# File 'lib/active_object/enumerable.rb', line 65

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

#frequencies ⇒ Object 



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# File 'lib/active_object/enumerable.rb', line 73

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

#incase?(object) ⇒ Boolean

rubocop:disable Style/CaseEquality

Returns:

  • (Boolean) 


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# File 'lib/active_object/enumerable.rb', line 78

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

#many? ⇒ Boolean

rubocop:enable Style/CaseEquality

Returns:

  • (Boolean) 


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# File 'lib/active_object/enumerable.rb', line 83

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

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



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# File 'lib/active_object/enumerable.rb', line 95

def mean(identity = 0)
  return identity if empty?

  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 104

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

  return(identity) unless collection_length > 0.0

  half_collection = collection_length / 2.0
  sorted_collection = collection_sorted[half_collection]

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

#mode(identity = 0) ⇒ Object

rubocop:disable Metrics/AbcSize



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# File 'lib/active_object/enumerable.rb', line 121

def mode(identity = 0)
  return identity unless length.positive?

  frequency_distribution = each_with_object(Hash.new(0)) { |val, hsh| hsh[val] += 1 }
  frequency_top_two = frequency_distribution.sort_by { |_, val| -val }.take(2)
  top_two_first = frequency_top_two.first

  return if frequency_top_two.length != 1 && top_two_first.last == frequency_top_two.last.last
  top_two_first.first
end

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

rubocop:ensable Metrics/AbcSize



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# File 'lib/active_object/enumerable.rb', line 133

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

#percentile(num, identity = 0) ⇒ Object 



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# File 'lib/active_object/enumerable.rb', line 141

def percentile(num, identity = 0)
  return identity unless length.positive?

  collection_sorted = sort
  rank = (num.to_f / 100) * (length + 1)

  if rank.fraction?
    sample_0 = collection_sorted[rank.truncate - 1]
    sample_1 = collection_sorted[rank.truncate]

    (rank.fraction * (sample_1 - sample_0)) + sample_0
  else
    collection_sorted[rank - 1]
  end
end

#range(identity = 0) ⇒ Object 



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# File 'lib/active_object/enumerable.rb', line 157

def range(identity = 0)
  return identity unless length.positive?

  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 164

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

#standard_deviation(identity = 0) ⇒ Object 



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# File 'lib/active_object/enumerable.rb', line 174

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 180

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

#take_last(num) ⇒ Object 



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

def take_last(num)
  collection_length = to_a.length

  return self if num > collection_length

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

#take_last_if ⇒ Object 



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# File 'lib/active_object/enumerable.rb', line 196

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

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

#variance(identity = 0) ⇒ Object 



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# File 'lib/active_object/enumerable.rb', line 204

def variance(identity = 0)
  collection_length = length

  return identity if collection_length <= 1

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