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November 6, 2013 23:23
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resistor_calculator.rb
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class ResistorCalculator | |
# http://www.dannyg.com/examples/res2/resistor.htm | |
attr_reader :tolerance, :multiplier, :ones, :tens, :ohms | |
Tens = %w[Black Brown Red Orange Yellow Green Blue Violet Gray White] | |
Ones = %w[Black Brown Red Orange Yellow Green Blue Violet Gray White] | |
Multiplier = %w[Black Brown Red Orange Yellow Green Blue Violet Gray White Gold Silver] | |
Tolerance = %w[Gold Silver None] | |
MultiplierValues = [ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, -2 ] | |
ToleranceValues = [ 5, 10, 20 ] | |
def initialize(tens="Black", ones="Black", multiplier="Black", tolerance="Gold") | |
@tens, @ones, @multiplier, @tolerance = *[tens, ones, multiplier, tolerance].map(&:capitalize) | |
raise "Invalid Color #{@tens} for Tens" unless Tens.include?(@tens) | |
raise "Invalid Color #{@ones} for Ones" unless Ones.include?(@ones) | |
raise "Invalid Color #{@multiplier} for Multiplier" unless Multiplier.include?(@multiplier) | |
raise "Invalid Color #{@tolerance} for Tolerance" unless Tolerance.include?(@tolerance) | |
calculate_ohms | |
end | |
def calculate_ohms | |
ohmage = (Tens.index(@tens) * 10.0) + Ones.index(@ones) | |
@ohms = ohmage * (10**MultiplierValues[Multiplier.index(@multiplier)]) | |
end | |
def to_f; calculate_ohms; end | |
def to_i; calculate_ohms.to_i; end | |
def to_s; "%s +/-%d%%" % [format(calculate_ohms), ToleranceValues[Tolerance.index(@tolerance)]]; end | |
def inspect | |
"Resistor.new(%s, %s, %s, %s) = %s" % | |
[ @tens, @ones, @multiplier, @tolerance, to_s ] | |
end | |
def format(ohmage) | |
if ohmage >= 1e6 | |
"%g Mohms" % (ohmage / 1e6) | |
else | |
ohmage >= 1e3 ? "%g Kohms" % (ohmage / 1e3) : "%g ohms" % ohmage | |
end | |
end | |
def self.[](*a); new(*a).to_s; end | |
end | |
p ResistorCalculator["red", "red", "red", "gold"] | |
__END__ | |
p ResistorCalculator.new("green", "green", "red", "gold").inspect | |
p ResistorCalculator.new("green", "green", "red", "gold").to_f | |
p ResistorCalculator.new("green", "green", "red", "gold").to_i | |
p ResistorCalculator.new("green", "green", "red", "gold").to_s | |
p ResistorCalculator["green", "green", "red", "gold"] | |
p ResistorCalculator["green", "green", "brown", "gold"] | |
p ResistorCalculator["green", "green", "gold", "gold"] | |
p ResistorCalculator["brown", "black", "red", "gold"] |
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