Difference between revisions of "Ruby Number Classes and Conversions"

Revision as of 21:03, 15 November 2007

Just about everything in Ruby is an object. Perhaps one of most surprising things is that even numbers are objects in Ruby. Most other programming languages treat numbers as primitives (which essentially means theyt are the building blocks from which objects are built). This means that each number type is associated with a number class, along with the various methods associated with that class.

Contents

	Contents 1 Ruby Number Classes 1.1 Integer Class 1.2 Fixnum Class 1.3 Bignum Class 1.4 Float Class 1.5 Rational Class 2 Converting Numbers in Ruby 2.1 Convert Floating Point Number to an Integer 2.2 Convert a String to an Integer 2.3 Convert a Hexadecimal Number to an Integer 2.4 Convert an Octal Number to an Integer 2.5 Convert a Binary Number to an Integer 2.6 Convert an Character to the ASCII Character Code 2.7 Convert an Integer Floating Point 2.8 Convert a String to Floating Point 2.9 Convert a Hexadecimal Number to Floating Point 2.10 Convert an Octal Number to a Floating Point 2.11 Convert a Binary Number to Floating Point 2.12 Convert an Character to a Floating Point ASCII Character Code

Ruby Number Classes

Ruby provides a number of builtin number classes. In this section we will explore some of the more commonly used classes.

Integer Class

The base class from which the following number classes are derived.

Fixnum Class

A Fixnum holds Integer values that can be represented in a native machine word (minus 1 bit). This effectively means that the maximum range of a Fixnum value depends on the architecture of the system on which the code is executing.

If an operation performed on a Fixnum exceeds range defined by the system's marchine word, the value is automatically converted by the interpreter to a Bignum.

Bignum Class

Bignum objects hold integers that fall outside the range of the Ruby Fixnum class. When a calculation involving Bignum objects returns a result that will fit in a Fixnum, the result is converted to Fixnum.

Float Class

The Float object represents real numbers based on the native architecture‘s double-precision floating point representation.

Rational Class

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.

Converting Numbers in Ruby

Numbers can be converted from type to another using the Ruby Integer and Float methods. This methods takes as an argument the value to be converted. For example:

Convert Floating Point Number to an Integer

Integer (10.898)
=> 10

Convert a String to an Integer

Integer ("10898")
=> 10898

Convert a Hexadecimal Number to an Integer

Integer (0xA4F5D)
=> 675677

Convert an Octal Number to an Integer

Integer (01231)
=> 665

Convert a Binary Number to an Integer

Integer (01110101)
=> 299073

Convert an Character to the ASCII Character Code

Integer (?e)
=> 101

Similarly, we can perform conversions to floating point using the Float method:

Convert an Integer Floating Point

Float (10)
=> 10.0

Convert a String to Floating Point

Float ("10.09889")
=> 10.09889

Convert a Hexadecimal Number to Floating Point

Float (0xA4F5D)
=> 675677.0

Convert an Octal Number to a Floating Point

Float (01231)
=> 665.0

Convert a Binary Number to Floating Point

Float (01110101)
=> 299073.0

Convert an Character to a Floating Point ASCII Character Code

Float (?e)
=> 101.0