Class: Rational

Rational implements a rational class for numbers.

A rational number is a number that can be expressed as a fraction p/q where p and q are integers and q != 0. A rational number p/q is said to have numerator p and denominator q. Numbers that are not rational are called irrational numbers. (mathworld.wolfram.com/RationalNumber.html)

To create a Rational Number:

  Rational(a,b)             # -> a/b
  Rational.new!(a,b)        # -> a/b

Examples:

  Rational(5,6)             # -> 5/6
  Rational(5)               # -> 5/1

Rational numbers are reduced to their lowest terms:

  Rational(6,10)            # -> 3/5

But not if you use the unusual method "new!":

  Rational.new!(6,10)       # -> 6/10

Division by zero is obviously not allowed:

  Rational(3,0)             # -> ZeroDivisionError

Methods

% * ** + - / <=> == abs coerce divmod hash inspect new new! reduce to_f to_i to_r to_s

Attributes

denominator	[R]
numerator	[R]

Public Class methods

new(num, den)

This method is actually private.

new!(num, den = 1)

Implements the constructor. This method does not reduce to lowest terms or check for division by zero. Therefore Rational() should be preferred in normal use.

reduce(num, den = 1)

Reduces the given numerator and denominator to their lowest terms. Use Rational() instead.

Public Instance methods

%(other)

Returns the remainder when this value is divided by other.

Examples:

  r = Rational(7,4)    # -> Rational(7,4)
  r % Rational(1,2)    # -> Rational(1,4)
  r % 1                # -> Rational(3,4)
  r % Rational(1,7)    # -> Rational(1,28)
  r % 0.26             # -> 0.19

*(a)

Returns the product of this value and a.

Examples:

  r = Rational(3,4)    # -> Rational(3,4)
  r * 2                # -> Rational(3,2)
  r * 4                # -> Rational(3,1)
  r * 0.5              # -> 0.375
  r * Rational(1,2)    # -> Rational(3,8)

**(other)

Returns this value raised to the given power.

Examples:

  r = Rational(3,4)    # -> Rational(3,4)
  r ** 2               # -> Rational(9,16)
  r ** 2.0             # -> 0.5625
  r ** Rational(1,2)   # -> 0.866025403784439

+(a)

Returns the addition of this value and a.

Examples:

  r = Rational(3,4)      # -> Rational(3,4)
  r + 1                  # -> Rational(7,4)
  r + 0.5                # -> 1.25

-(a)

Returns the difference of this value and a. subtracted.

Examples:

  r = Rational(3,4)    # -> Rational(3,4)
  r - 1                # -> Rational(-1,4)
  r - 0.5              # -> 0.25

/(a)

Returns the quotient of this value and a.

  r = Rational(3,4)    # -> Rational(3,4)
  r / 2                # -> Rational(3,8)
  r / 2.0              # -> 0.375
  r / Rational(1,2)    # -> Rational(3,2)

<=>(other)

Standard comparison operator.

==(other)

Returns true iff this value is numerically equal to other.

But beware:

  Rational(1,2) == Rational(4,8)          # -> true
  Rational(1,2) == Rational.new!(4,8)     # -> false

Don‘t use Rational.new!

abs()

Returns the absolute value.

coerce(other)

divmod(other)

Returns the quotient and remainder.

Examples:

  r = Rational(7,4)        # -> Rational(7,4)
  r.divmod Rational(1,2)   # -> [3, Rational(1,4)]

hash()

Returns a hash code for the object.

inspect()

Returns a reconstructable string representation:

  Rational(5,8).inspect     # -> "Rational(5, 8)"

to_f()

Converts the rational to a Float.

to_i()

Converts the rational to an Integer. Not the nearest integer, the truncated integer. Study the following example carefully:

  Rational(+7,4).to_i             # -> 1
  Rational(-7,4).to_i             # -> -2
  (-1.75).to_i                    # -> -1

In other words:

  Rational(-7,4) == -1.75                 # -> true
  Rational(-7,4).to_i == (-1.75).to_i     # false

to_r()

Returns self.

to_s()

Returns a string representation of the rational number.

Example:

  Rational(3,4).to_s          #  "3/4"
  Rational(8).to_s            #  "8"