In Ruby, as in most of programming, whole numbers are referred to as integers, while fractions (or numbers with decimal points) are referred to as floats, or floating-point numbers. An integer can be a sequence of numbers, or digits, as long as you want. 1 is an integer, as is 50, as is 9128083901230. You get the picture.
In this guide, we’ll go over what you need to know about Ruby integer objects. For more Ruby tips, check out this beginner’s Ruby programming course, or this guide that teaches you how to use the Ruby on Rails framework.
What is an Integer, Anyway?
The definition of an integer, programming aside, is simply a whole number free of fractional component. This means 10 is an integer, but 10.5, or 10 1/2 are not. In programming, integers are usually treated like primitives, which are some of the most basic operations you can find in programming.
Ruby is different, in that it treats integers as actual objects. What this means is integers, like any other object, are associated with classes. For integers, those classes are Fixnum and Bignum.
Fixnum and Bignum
They might sound funny, but fixnum and bignum are really important when we’re talking Ruby integers. In Ruby, integers are just objects, part of the larger classes fixnum and bignum. To learn more about classes and class hierarchy in programming, consider taking a class on programming fundamentals. An entry-level course like that one will teach you all the basic programming concepts you need to know to understand the information presented in this guide.
- What is Fixnum?
Fixnum is a class in Ruby that contains objects with immediate value, or integers that can be conveyed via machine word. Fixnum objects are immutable, which means you can’t alter them after they’ve been created. When a Fixnum object is assigned as a parameter, rather than a reference to the Fixnum object being passed, the Fixnum object itself is passed.
- What is Bignum?
If a Fixnum object exceeds its range, it converts into a Bignum object. Unlike Fixnum objects, Bignum objects do not have immediate values.
Difference Between Ruby Integer and Float
As mentioned before, an integer must be a whole, real number. For fractions or other inexact numbers, we create floating point numbers, or float objects, instead.
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Converting To and From Integers
You can convert numbers in Ruby, meaning you can convert an inexact number like a float into a whole integer, as it suits your needs.
To convert a floating point number in Ruby to a Ruby integer, you’d simply wrap the float in an integer, as shown below:
Integer (950.12) => 950
In the example above, Ruby simply rounded the floating number 950.12 down to 950, which is a whole integer. You can convert strings to an integer in the same way!
Integer ("587920") => 587920
If you’re starting with integers, you can convert these to strings or floats as well. To convert an integer into a floating point number, simply wrap it in float, like so:
Float (20) => 20.0
20.0 is still a whole number, literally and mathematically, but programmatically, Ruby reads it as a float, since there’s a decimal. It’s still just 20, but in Ruby, if it’s 20.0, it needs to be treated as a float.
See below for more integer conversion tips. For more on converting numbers in Ruby, and other important concepts, check out this beginner’s Ruby tutorial course.
- Hexadecimal number to integer
Integer (0x13792) => 79762
- Octal number to integer
Integer (02350) => 1256
- Binary number to integer
Integer (0b11101010110) => 1878
Want to learn how to do hex and binary conversions in your head? Check out this course on mental math hex and binary conversions.
What Can You Do With An Integer?
The Ruby language comes with a huge set of operators, which are essential when working with integers. From arithmetic to assignment operators, below is a list of ones you’ll be using alongside your work with integers.
For more on Ruby operators and how to use them, you can check out this beginner’s Ruby programming course.
Arithmetic Operators in Ruby
- + for adding value to either operand
- – for subtracting the operand on the right from the operand on the left
- * for multiplying values on whichever side of the operator
- / for dividing the operand on the left by the operand on the right
- % called the modulus, similar to division above but also returns the remainder
- ** used to perform exponential calculations
Assignment Operators in Ruby
- = assigns value from the right to to the left operand
- += adds the operand on the right to the one on the left, and assigns the resulting value to the operand on the left
- -= does the same as above, but with subtraction
- *= does the same as above, but with multiplication
- /= does the same as above, but with division
- %= returns the modulus and assigns the remainder to the operand on the left
- **= performs exponential calculations and then assigns the resulting value to the operand on the left
Comparison Operators in Ruby
- == checks for equality between the two operands, and returns true if they are equal
- != checks for equality between the two operands, and returns true if they are not equal
- > checks if the value of the operand on the left is greater than the value of the one on the right, and returns true if the condition is met
- < checks if the value of the operand on the left is less than the value of the one on the right, and returns true if the condition is met
- >= checks if the value of the operand on the left is greater than or equal to the value of the one on the right, and returns true if the condition is met
- <= checks if the value of the operand on the left is less than or equal to the value of the one on the right, and returns true if condition is met
Want more Ruby help? Check out this advanced Ruby programming course for a more in-depth look at the language, or get started with Ruby’s most popular framework, Ruby on Rails.