Class: RubyTechnicalAnalysis::BollingerBands

Inherits:
Indicator
  • Object
show all
Defined in:
lib/ruby_technical_analysis/indicators/bollinger_bands.rb

Overview

Bollinger Bands

Find more information at: www.fidelity.com/learning-center/trading-investing/technical-analysis/technical-indicator-guide/bollinger-bands

Instance Attribute Summary collapse

Attributes inherited from Indicator

#series

Instance Method Summary collapse

Methods inherited from Indicator

call

Constructor Details

#initialize(series: [], period: 20, standard_deviations: 2) ⇒ BollingerBands

Returns a new instance of BollingerBands.

Parameters:

  • series (Array) (defaults to: []) —

    An array of prices, typically closing prices

  • period (Integer) (defaults to: 20) —

    The number of periods to use in the calculation

  • standard_deviations (Integer) (defaults to: 2) —

    The number of standard deviations to use in the calculation



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# File 'lib/ruby_technical_analysis/indicators/bollinger_bands.rb', line 11

def initialize(series: [], period: 20, standard_deviations: 2)
  @period = period
  @standard_deviations = standard_deviations

  super(series: series)
end

Instance Attribute Details

#period ⇒ Object (readonly)

Returns the value of attribute period.



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# File 'lib/ruby_technical_analysis/indicators/bollinger_bands.rb', line 6

def period
  @period
end

#standard_deviations ⇒ Object (readonly)

Returns the value of attribute standard_deviations.



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# File 'lib/ruby_technical_analysis/indicators/bollinger_bands.rb', line 6

def standard_deviations
  @standard_deviations
end

Instance Method Details

#call ⇒ Array

Returns An array containing the current upper, middle, and lower bands of the series.

Returns:

  • (Array) —

    An array containing the current upper, middle, and lower bands of the series



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# File 'lib/ruby_technical_analysis/indicators/bollinger_bands.rb', line 19

def call
  calculate_bollinger_bands
end

#valid? ⇒ Boolean

Returns Whether or not the object is valid.

Returns:

  • (Boolean) —

    Whether or not the object is valid



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# File 'lib/ruby_technical_analysis/indicators/bollinger_bands.rb', line 24

def valid?
  period <= series.length && standard_deviations > 0
end