Array Sort Ruby

Ruby is a simplistic and powerful programming language that provides exceptional features for daily programming operations.

Because arrays are a fundamental object in Ruby and other programming languages, Ruby provides a way to sort elements without writing an excellent custom algorithm.

This guide will teach you how to sort an array by using Ruby’s built-in methods and functionalities.

How to Sort An Array

Ruby provides various ways to sort an array. The sort and sort_by methods in Ruby are some of the most fundamental for sorting an array.

#1: Using the sort method

The sort method is defined in the Enumerable module, and it returns the values of the array sorted.

For example:

nums = [1,20, 23, 28, 2, 100, 34, 53, 22, 21, 11]

print nums.sort

[1, 2, 11, 20, 21, 22, 23, 28, 34, 53, 100]

By default, the method will return the items in the array sorted in ascending order.

It works using the spaceship operator, which returns 1 if a value is greater than, 0 for equal to, and -1 for less than.

If you provide an array of strings, the sorted array will be in alphabetical order as:

databases = %w{MySQL, PostgreSQL, Redis, Memcached, MongoDB, Elasticsearch}

print databases.sort

["Elasticsearch", "Memcached,", "MongoDB,", "MySQL,", "PostgreSQL,", "Redis,"]

You can pass a block to the sort function if you want to implement a custom sorting order. For example, the following implements a reverse order using the sort method.

nums = [1, 2, 11, 20, 21, 22, 23, 28, 34, 53, 100]

print nums.sort {|x, y| y <=> x}

[100, 53, 34, 28, 23, 22, 21, 20, 11, 2, 1]

Ruby also allows you to sort an array in place using the sort! method. The method will affect the original method into the new sorted array as:

nums = [1, 2, 11, 20, 21, 22, 23, 28, 34, 53, 100]


print nums

[1, 2, 11, 20, 21, 22, 23, 28, 34, 53, 100]

NOTE: Use the sort! method with caution; it overwrites the original array, as shown in the example above.

#2: Sort_by method

The sort_by method provides flexibility when sorting compared to the sort method. Let us look at a few examples to see how sorting using the sort_by method works.

The first example is sorting by the length of a string.

databases = ["Elasticsearch", "Memcached,", "MongoDB,", "MySQL,", "PostgreSQL,", "Redis"]

print databases.sort_by {|content| content.length}

["Redis", "MySQL,", "MongoDB,", "Memcached,", "PostgreSQL,", "Elasticsearch"]

Sorting of the elements in the array happens in ascending order based on the string content length.

We use the length property of the string as the sort_by method expects a numerical value.

Suppose we want to sort the string in reverse order using the sort_by method? In such a case, we can add a minus operator in length, as shown below:

databases = ["Elasticsearch", "Memcached,", "MongoDB,", "MySQL,", "PostgreSQL,", "Redis"]

print databases.sort_by {|content| -content.length}

The above example will return the sorted array in descending order.


This guide has shown you how to work with arrays and sort them using built-in Ruby methods.

About the author

John Otieno

My name is John and am a fellow geek like you. I am passionate about all things computers from Hardware, Operating systems to Programming. My dream is to share my knowledge with the world and help out fellow geeks. Follow my content by subscribing to LinuxHint mailing list