Data Structures - Arrays for Beginners

Elliot Forbes ⏰ 3 Minutes 📅 Dec 20, 2017

In this article we are going to be looking at the array data structure. We’ll be looking at some of the fundamental characteristics of the structure and how we can best leverage this within our own programs.


Arrays represent a collection of elements, these elements can be of different types; integers, characters, strings, floating-point values and even composite types such as arrays which allows you to create nested array structures should you wish, or objects which are a group of elements all bundled together.

For example, say we wanted to store a list of names. We could use an array which would contain all of the names we want like so:

["Elliot", "Fraser"]

Or if we wanted to have an array of the months of the year then we could easily define our array like so:

["January", "february", "march", "april", "may", "june", "july", "august", "september", "october", "november", "december"]

Arrays offer an incredible amount of flexibility to programmers as we can store any number of items we wish within them and you’ll find arrays in almost every programming language you work with.

Access Elements in Arrays

In order for us to access any elements in an array we typically have to use integers as our array’s indices. For example if we wanted to access the first element in an array we would typically use my_array[0]. This presumes the language implements the array so that they start at 0 and not at 1.

Resizing Arrays

In most languages arrays are of a fixed length, if you try to insert more elements into an array than there are allocated spaces then you will typically be hit with an exception.

In these scenarios you will typically have to go through the following procedure:

  1. Create a new array with double the size
  2. Copy all of the elements of the old array over to the new array
  3. Delete the old array

As you can imagine this is a rather expensive task for larger arrays and can adversely impact the performance of your systems.

Note: In some languages there exist implementations that will automatically handle array resizing.

Arrays Used In Other Data Structures

It should be noted that arrays can be used within other data structures. For example, you can implement binary trees as well as hash tables using arrays. I’ll be covering exactly how this works in their respective tutorials.


I hope you found this tutorial useful! If you did or you require further assistance then please feel free to let me know in the comments section below or by tweeting me: @Elliot_F.