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Contents
# frozen_string_literal: true
module Cotcube
module Indicators
# returns the difference between the current value and the first available value in carrier.
# if block given, the block is evaluated as conditional, using current and carrier.get.last.
# if evaluation is false, carrier remains untouched and 0 is returned
def change(key:, lookback: 1, debug: false)
unless lookback.is_a?(Integer) && (lookback >= 1)
raise ArgumentError, 'invalid lookback period, need integer >= 1'
end
carrier = Cotcube::Indicators::Carrier.new(length: lookback + 1)
lambda do |x|
current = x[key.to_sym]
current = 0 unless current.is_a?(Numeric)
carrier << 0 if carrier.empty?
if debug
puts "comparing #{current} from #{key.to_sym} ... "\
"#{lookback} ... #{carrier.inspect} ... yield"\
" #{block_given? ? yield(carrier.get.last, current) : ''}"
end
if (not block_given?) || yield(carrier.get.last, current) # rubocop:disable Style/GuardClause
carrier << current
ret = carrier.size < lookback + 1 ? 0 : (carrier.get.last - carrier.get.first)
return ret.to_f
else
return 0
end
end
end
end
end
Version data entries
7 entries across 7 versions & 1 rubygems