Using a ruby method to return the absolute value of a number

Using a ruby method to return the absolute value of a number

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Revisited on May 18th, 2023

TL; DR: The fabulous method is called abs


Hey guys.


In the world of mathematics and programming, absolute numbers play a crucial role in numerous applications. They provide us with a clear and definitive measure, stripping away any notion of direction and leaving us with a value's magnitude alone.

In the realm of Ruby programming, the abs method becomes our trusted ally when we seek to harness the power of absolute numbers.

Let's dive in.

Absolute value


An absolute value, also known as the magnitude, is a mathematical concept that represents the distance of a number from zero on a number line. It disregards the number's direction or sign and focuses solely on its numerical value. In other words, the absolute value of a number is always positive or zero.

For example, consider the number line with points representing -5, -3, 0, 2, and 4. The absolute value of -5 is 5, the absolute value of -3 is 3, the absolute value of 0 remains 0, the absolute value of 2 is 2, and the absolute value of 4 is 4. Regardless of the numbers' position on the number line, their absolute values provide a measure of their magnitude without considering their positive or negative nature.


In programming, the absolute value is an essential concept for performing calculations, comparisons, and transformations. Many programming languages, including Ruby, provide built-in functions or methods, such as the abs method in Ruby, to conveniently obtain the absolute value of a number without the need for manual calculations.

The Abs method

The abs method in Ruby is a versatile tool that allows us to effortlessly obtain the absolute value of a number. Whether we're dealing with integers, floats, or complex numbers, the abs method comes to our rescue, providing a concise and elegant solution to ensure our calculations remain accurate and reliable.

Throughout our journey, we will witness the abs method's ability to transform negative numbers into positive ones, helping us compare values, calculate distances, or enforce constraints in our programs.


The abs belongs to the numeric class. In Ruby, the numeric class is the highest-level class for numbers.

The abs method returns the absolute value of a given number.

The magnitude method is an alias for the abs method.


The syntax is very simple:


number is the value we want to check the absolute version. . is how we call the method. abs is the method.

Coding time

Let's check it out:

irb(main):006:0> -9.abs
=> 9

The absolute value of a positive number is the number itself

irb(main):005:0> 9.abs
=> 9

Since The abs method also works with the float type:

rb(main):007:0> -3.4.abs
=> 3.4
irb(main):008:0> 3.4.abs
=> 3.4

A NoMethodError is displayed if it's used with a data type that it doesn't inherit from the numeric class.

irb(main):009:0> "1".abs
Traceback (most recent call last):
        4: from /usr/local/bin/irb:23:in `<main>'
        3: from /usr/local/bin/irb:23:in `load'
        2: from /var/lib/gems/2.5.0/gems/irb-1.1.0/exe/irb:11:in `<top (required)>'
        1: from (irb):9
NoMethodError (undefined method `abs' for "1":String)

Summing up:

  • Syntax: numericvalue.abs()

  • Parameter: numeric value which is to be converted to absolute value.

  • Return: absolute value of the passed numeric value.

Final thoughts

In this article, it was possible to learn and practice how to get the absolute value of numbers in Ruby.

Hope it was useful. That's for today. Let me know if you have any questions.

By the way, you help me a lot if you like and/or share this article.