How To Calculate Bollinger Bands using Ruby?

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require 'csv'
require 'statistics2'


def calculate_bollinger_bands(data, window_size, num_standard_deviations)
  bands = []
  data.each_cons(window_size) do |window|
    middle_band = window.sum / window_size.to_f
    standard_deviation = Statistics2.standard_deviation(window)
    upper_band = middle_band + num_standard_deviations * standard_deviation
    lower_band = middle_band - num_standard_deviations * standard_deviation
    bands << [upper_band, middle_band, lower_band]
  end
  bands
end


# Example usage:
# Load data from CSV file (assuming the first column is the price data)
data = CSV.read('your_data.csv', converters: :numeric).transpose[0]


# Set parameters
window_size = 20
num_standard_deviations = 2


# Calculate Bollinger Bands
bollinger_bands = calculate_bollinger_bands(data, window_size, num_standard_deviations)


# Display the Bollinger Bands
puts "Upper Band, Middle Band, Lower Band"
bollinger_bands.each do |band|
  puts "#{band[0]}, #{band[1]}, #{band[2]}"
end

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require 'finance'

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def calculate_bollinger_bands(data, window_size=20, num_std_dev=2)
  bb = Finance::BollingerBands.new(data, window_size, num_std_dev)
  upper_band = bb.upper_band
  lower_band = bb.lower_band
  middle_band = bb.mid_band

  return upper_band, lower_band, middle_band
end

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data = [10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30]

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upper_band, lower_band, middle_band = calculate_bollinger_bands(data)

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puts "Upper Band: #{upper_band}"
puts "Lower Band: #{lower_band}"
puts "Middle Band: #{middle_band}"