An Introduction to Ruby Numbers Methods

Basics:

  • Ruby has two categories of numbers - integers and floating-point (also called floats).
  • Integers are whole numbers that can be positive or negative but cannot be fractions.
  • Depending on their size, integers can have the class Fixnum or Bignum .
  • Floats are numbers with a decimal place.

Examples:

x = 5.5
x.class
# returns
Float

x = 5
x.class
# returns
Fixnum

x = 11122233344455566677
x.class
# returns
Bignum # basically, Bignum is a very large number
# <a href='http://ruby-doc.org/core-2.0.0/Bignum.html' target='_blank' rel='nofollow'>read this article for more info</a>

In Ruby there are a variety of build in methods you can perform on numbers.

Even:

  • Use .even? to check whether or not an integer is even.
15.even?
4.even?
# returns:
false
true

Odd:

  • Use .odd? to check whether or not an integer is odd.
15.odd?
4.odd?
# returns:
true
false

Ceil:

  • The .ceil method rounds up to the nearest integers.
8.3.ceil
6.7.ceil
# returns:
9
7

Floor:

  • The .floor method rounds down to the nearest integers.
8.3.floor
6.7.floor
# returns:
8
6

Next:

  • Use .next to return the next consecutive integer.
15.next
2.next
-4.next
# returns:
16
3
-3

To String:

  • The .to_s method changes an integer into a string.
15.to_s
# returns:
"15"

Greatest Common Denominator:

  • The .gcd method returns the greatest common denominator of two numbers.
15.gcd(5)
9.gcd(4)
# returns:
5
1