Array.rb

class Array
  def delete_first_occurence!(array=nil)
    return nil if array.nil? || !array.is_a?(Array)

    array.each do |item|
      self.delete_at(self.index(item)) if self.index(item)
    end
    self
  end

  def delete_first_occurence(array=nil)
    return nil if array.nil? || !array.is_a?(Array)
    _return_ = self.dup

    array.each do |item|
      _return_.delete_at(self.index(item)) if self.index(item)
    end

    _return_
  end
  
  def delete_first_occurence_reverse!(array=nil)
    return nil if array.nil? || !array.is_a?(Array)
    self.reverse!
    
    array.each do |item|
      self.delete_at(self.index(item)) if self.index(item)
    end
    
    self.reverse!
  end

  def delete_first_occurence_reverse(array=nil)
    return nil if array.nil? || !array.is_a?(Array)
    _return_ = self.dup.reverse

    array.each do |item|
      _return_.delete_at(self.index(item)) if self.index(item)
    end

    _return_.reverse!
  end
end