Class: Fractional
Constant Summary
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- SINGLE_FRACTION =
/^\s*(\-?\d+)\/(\-?\d+)\s*$/
- MIXED_FRACTION =
/^\s*(\-?\d*)\s+(\d+)\/(\d+)\s*$/
Class Method Summary
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Instance Method Summary
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fraction?, mixed_fraction?, single_fraction?
Constructor Details
#initialize(value, options = {}) ⇒ Fractional
Returns a new instance of Fractional.
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# File 'lib/fractional.rb', line 10
def initialize( value, options={} )
case value
when Rational
@value = value
when String
@value = Fractional.string_to_fraction( value, options )
when Fixnum
@value = Rational(value)
when Numeric
@value = Fractional.float_to_fraction( value.to_f, options )
else
raise TypeError, "Cannot instantiate Fractional from #{value.class}"
end
end
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Dynamic Method Handling
This class handles dynamic methods through the method_missing method
#method_missing(name, *args, &blk) ⇒ Object
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# File 'lib/fractional.rb', line 26
def method_missing(name, *args, &blk)
return_value = @value.send(name, *args, &blk)
return_value.is_a?(Rational) ? Fractional.new(return_value) : return_value
end
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Class Method Details
.find_after_decimal(decimal) ⇒ Object
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# File 'lib/fractional.rb', line 175
def self.find_after_decimal( decimal )
s_decimal = decimal.to_s
regex = /(#{find_repeat(s_decimal)})+/
last = s_decimal.index( regex )
first = s_decimal.index( '.' ) + 1
s_decimal[first...last]
end
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.find_before_decimal(decimal) ⇒ Object
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# File 'lib/fractional.rb', line 183
def self.find_before_decimal( decimal )
numeric = decimal.to_f.truncate.to_i
if numeric == 0
decimal.to_f < 0 ? "-0" : "0"
else
numeric.to_s
end
end
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.find_repeat(decimal) ⇒ Object
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# File 'lib/fractional.rb', line 192
def self.find_repeat( decimal )
return largest_repeat( decimal.to_s.reverse, 0 ).reverse
end
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.float_to_fraction(value, options = {}) ⇒ Object
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# File 'lib/fractional.rb', line 107
def self.float_to_fraction( value, options={} )
if value.to_f.nan?
return Rational(0,0) elsif value.to_f.infinite?
return Rational(value<0 ? -1 : 1,0) end
if options[:to_nearest]
return self.round_to_nearest_fraction( value, options[:to_nearest] )
end
unless options[:exact]
repeat = float_to_rational_repeat(value)
return repeat unless repeat.nil?
end
return Rational(value.to_s)
end
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.float_to_rational_repeat(base_value) ⇒ Object
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# File 'lib/fractional.rb', line 155
def self.float_to_rational_repeat(base_value)
normalized_value = base_value.to_f
repeat = find_repeat( normalized_value )
if repeat.nil? or repeat.length < 1
normalized_value = normalized_value.to_s[0...-1].to_f
repeat = find_repeat(normalized_value.to_s)
end
if !repeat or repeat.length < 1
return nil
else
return fractional_from_parts(
find_before_decimal(normalized_value),
find_after_decimal(normalized_value),
repeat)
end
end
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.fractional_from_parts(before_decimal, after_decimal, repeat) ⇒ Object
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# File 'lib/fractional.rb', line 209
def self.fractional_from_parts(before_decimal, after_decimal, repeat)
numerator = "#{before_decimal}#{after_decimal}#{repeat}".to_i - "#{before_decimal}#{after_decimal}".to_i
denominator = 10 ** (after_decimal.length + repeat.length) - 10 ** after_decimal.length
return Rational( numerator, denominator )
end
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.largest_repeat(string, i) ⇒ Object
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# File 'lib/fractional.rb', line 196
def self.largest_repeat( string, i )
if i * 2 > string.length
return ""
end
repeat_string = string[0..i]
next_best = largest_repeat( string, i + 1)
if repeat_string == string[i+1..2*i + 1]
repeat_string.length > next_best.length ? repeat_string : next_best
else
next_best
end
end
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.round_to_nearest_fraction(value, to_nearest_fraction) ⇒ Object
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# File 'lib/fractional.rb', line 215
def self.round_to_nearest_fraction(value, to_nearest_fraction)
to_nearest_float = Fractional.new(to_nearest_fraction).to_f
Fractional.new((Fractional.new(value).to_f / to_nearest_float).round * to_nearest_float)
end
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.string_is_fraction?(value) ⇒ Boolean
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# File 'lib/fractional.rb', line 143
def self.string_is_fraction?( value )
value.is_a? String and (value.match(SINGLE_FRACTION) or value.match(MIXED_FRACTION))
end
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.string_is_mixed_fraction?(value) ⇒ Boolean
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# File 'lib/fractional.rb', line 147
def self.string_is_mixed_fraction?( value )
string_is_fraction?(value) and value.match(MIXED_FRACTION)
end
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.string_is_single_fraction?(value) ⇒ Boolean
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# File 'lib/fractional.rb', line 151
def self.string_is_single_fraction?( value )
string_is_fraction?(value) and value.match(SINGLE_FRACTION)
end
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.string_to_fraction(value, options = {}) ⇒ Object
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# File 'lib/fractional.rb', line 130
def self.string_to_fraction( value, options={} )
if string_is_mixed_fraction?(value)
whole, numerator, denominator = value.scan(MIXED_FRACTION).flatten
return Rational( (whole.to_i.abs * denominator.to_i + numerator.to_i) *
whole.to_i / whole.to_i.abs, denominator.to_i )
elsif string_is_single_fraction?(value)
numerator, denominator = value.split("/")
return Rational(numerator.to_i, denominator.to_i)
else
return float_to_fraction(value.to_f, options)
end
end
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Instance Method Details
#<=>(other) ⇒ Object
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# File 'lib/fractional.rb', line 70
def <=>(other)
case other
when Fractional, Rational
self.to_r <=> other.to_r
when Numeric
@value <=> other
when String
@value <=> Fractional.new(other).to_r
else
nil
end
end
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#==(other_num) ⇒ Object
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# File 'lib/fractional.rb', line 66
def ==( other_num )
@value == other_num
end
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#coerce(other) ⇒ Object
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# File 'lib/fractional.rb', line 83
def coerce(other)
case other
when Numeric
return Fractional.new(other), self
when String
return Fractional.new(other), self
else
raise TypeError, "#{other.class} cannot be coerced into #{Numeric}"
end
end
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#fractional_part ⇒ Object
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# File 'lib/fractional.rb', line 62
def fractional_part
@value - whole_part
end
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#to_f ⇒ Object
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# File 'lib/fractional.rb', line 46
def to_f
@value.to_f
end
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#to_i ⇒ Object
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# File 'lib/fractional.rb', line 54
def to_i
whole_part
end
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#to_r ⇒ Object
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# File 'lib/fractional.rb', line 50
def to_r
@value
end
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#to_s(options = {}) ⇒ Object
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# File 'lib/fractional.rb', line 31
def to_s( options={} )
if options[:mixed_fraction] or options[:mixed_number]
to_join = []
if whole_part != 0
to_join << whole_part.to_s
end
if fractional_part != 0
to_join << fractional_part.abs.to_s
end
to_join.join(" ")
else
@value.to_s
end
end
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#whole_part ⇒ Object
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# File 'lib/fractional.rb', line 58
def whole_part
@value.truncate
end
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