Ruby Data Types

In this chapter, we will introduce the basic data types in Ruby.

Ruby supports data types including basic Number, String, Ranges, Symbols, as well as special values like true, false, and nil. Additionally, there are two important data structures—Array and Hash.

---

Number Types

1. Integers

There are two types of integers. If within 31 bits (four bytes), it is an instance of Fixnum. If it exceeds that, it is an instance of Bignum.

The integer range is from -2³⁰ to 2³⁰-1. Integers within this range are objects of the class Fixnum. When the integer value is greater than or equal to 2 to the power of 30 (from -2⁶² to 2⁶²-1), it automatically converts to the Bignum type.

You can use an optional leading sign before the integer, an optional base indicator (0 for octal, 0x for hex, 0b for binary), followed by a string of digits. The underscore character is ignored in a number string.

You can get the integer value of an ASCII character or an escape sequence marked with a question mark.

Example

123
1_234
-500
0377
0xff
0b1011
"a".ord
?n
12345678901234567890
a1=0
a2=1_000_000
a3=0xa
puts a1,a2
puts a3
=begin
This is a comment.
Called: Embedded Document Comment
Similar to C
=end

Floating-Point Numbers

Ruby supports floating-point numbers. These are numbers with decimal points. Floating-point numbers are objects of the class Float and can be any of the following.

Example

123.4
1.0e6
4E20
4e+20
f1=0.0
f2=2.1
f3=1000000.1
puts f3

Arithmetic Operations

Addition, subtraction, multiplication, and division operators: + - * /. The exponentiation operator is **.

The exponent does not have to be an integer, for example:

Example

puts 2**(1/4) # 1 divided by 4 is 0, then 2 to the power of 0 is 1
puts 16**(1/4.0)

---

String Type

A Ruby string is simply a sequence of 8-bit bytes. They are objects of the class String.

Strings enclosed in double quotes allow substitution and the use of backslash notation. Strings enclosed in single quotes do not allow substitution and only permit the use of the two backslash sequences and '.

Example

puts 'escape using ""';
puts 'That's right';

Try it »

This will produce the following result:

escape using ""
That's right

You can use the sequence #{ expr } to substitute the value of any Ruby expression into a string. Here, expr can be any Ruby expression.

Example

puts "Multiplication: #{24*60*60}";

This will produce the following result:

Multiplication: 86400

Example

name="Ruby"
puts name
puts "#{name+", ok"}"

The output is:

Ruby
Ruby, ok

Backslash Notation

The following table lists the backslash notations supported by Ruby:

Notation	Character Represented
n	Newline (0x0a)
r	Carriage return (0x0d)
f	Formfeed (0x0c)
b	Backspace (0x08)
a	Bell (0x07)
e	Escape (0x1b)
s	Space (0x20)
nnn	Octal notation (n is 0-7)
xnn	Hexadecimal notation (n is 0-9, a-f, or A-F)
cx, C-x	Control-x
M-x	Meta-x (c | 0x80)
M-C-x	Meta-Control-x
	Backslash character

For more details about Ruby strings, please see Ruby Strings.

Arrays

Array literals are defined by a comma-separated list inside [] and support range definitions.

• (1) Arrays are accessed via [] indexing.
• (2) Elements are inserted, deleted, and replaced through assignment operations.
• (3) Arrays are merged and elements are deleted using the + and - operators, with the collections appearing as new collections.
• (4) Elements are appended to the original array using the << operator.
• (5) Array elements are repeated using the * operator.
• (6) Union and intersection operations are performed using the | and & operators (note the order).

Example

ary = ["fred", 10, 3.14, "This is a string", "last element", ]
ary.each do |i|
   puts i
end

Try it »

This will produce the following result:

fred
10
3.14
This is a string
last element

For more details about Ruby arrays, please see Ruby Arrays.

Hash Type

A Ruby hash is a series of key/value pairs placed inside curly braces. Keys and values are separated by a comma and the sequence =>. Trailing commas are ignored.

Example

hsh = colors = {
   "red" => 0xf00,
   "green" => 0x0f0,
   "blue" => 0x00f
}
hsh.each do |key, value|
   print key, " is ", value, "n"
end

Try it »

This will produce the following result:

red is 3840
green is 240
blue is 15

For more details about Ruby hashes, please see Ruby Hashes.

Range Type

A range represents an interval.

A range is represented by setting a starting value and an ending value. Ranges can be constructed using s..e and s...e, or via Range.new.

A range constructed with .. runs from the starting value to the ending value (inclusive of the ending value). A range constructed with ... runs from the starting value to the ending value (exclusive of the ending value). When used as an iterator, a range returns each value in the sequence.

The range (1..5) means it contains the values 1, 2, 3, 4, 5. The range (1...5) means it contains the values 1, 2, 3, 4.

Example

(10..15).each do |n|
   print n, ' '
end

Try it »

This will produce the following result:

10 11 12 13 14 15

For more details about Ruby ranges, please see Ruby Ranges.