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How to Learn Data Structures

Brandi Taylor - February 09, 2021


Data structures are collections used in computer science and programming to efficiently organize, store, and access data used by a program. As a programmer, it’s important to learn data structures to maintain efficiency within the program you’re writing.

What are Data Structures?

Programs utilize data structures to organize data for efficiency in the retrieval and manipulation of that data. When thinking of data structures, think of a collection of values and how they relate to each other within your program. Data structures are found in high-level programming languages such as JavaScript, Swift, Python, Java, and C#, and are a fundamental computer science concept.

What are Data Structures Used for?

Data Structures are used to make a program as efficient as possible and to create the best user experience without overloading the user’s system.  It’s important to learn data structures to organize and store data, and how to implement them within your program.

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When searching data structures, you’ll often come across the term “Data Structures and Algorithms”. Algorithms are determined methods used to store and access your data which is stored within a particular data structure in such a way that the amount of memory your program requires is reduced. Data structures help your program remain performant.

Types of Data Structures

Although they’re sometimes implemented differently, data structures are fairly consistent across all programming languages that support them. Some of the most common data structures are:

  • Lists (also known as arrays). Lists are a collection of data values stored together in memory. They are considered indexed collections and each value can be retrieved by an index (or location) within the list. Some programming languages like Swift guarantee the same order of elements within the array, while others like JavaScript do not guarantee order of elements. With a list, values can be inserted at a particular index, moved to a different index, or removed altogether.
  • Linked Lists. Linked lists can be singly or doubly linked. They are similar to lists and arrays as they are a collection of data nodes and values, though unlike lists or arrays, their nodes are not stored together in memory. In a Singly Linked List, each node stored in the list also contains a value and pointer to the next node in the list. In a Doubly Linked List, each node stored in the list contains a value and pointer to the next node in the list, as well as a value and a pointer to the previous node in the list.
  • Dictionaries. The concept is similar to how a human language dictionary is used to find a word (key) and a definition (value). Dictionaries are a data structure that uses a key/value pair to store data. When accessing data within a dictionary, you will often use the key to access the value associated with it. Although dictionaries may have different names in various programming languages (Dictionary in Swift and Python, or Object in JavaScript, for example), they are fundamentally the same across languages.
  • Stacks and Queues. Stacks are linear data structures that maintain the order of values. Values in a stack have to be added and removed in a particular order. A stack can be thought of as having a stack of papers. You can only add new papers by placing a new piece on top of the stack and to access the bottom paper, you must remove (in order) each piece of paper on top of it. Stacks follow the LIFO principle (Last In First Out) since the last value of the stack must be removed first to access any value before it.
  • Queues. Queues are similar to stacks, but follow the FIFO (First In First Out) principle. Just like a queue, or line of riders for a roller coaster, the first person in line is the first person out of line to board the ride. When adding values in a queue, you can only access latter values by removing the values that were added prior.

There are many other types of data structures such as Binary Trees, Graphs, Hash Tables, and Heaps. Each type of data structure has its own unique use case and advantages, and there are often reasons why a computer scientist or programmer will use one data type over another. It’s important to learn data structures as a programmer so you know which data structure is best suited for the data being stored so it can be efficiently accessed for use within the program.

Learning Data Structures

Having experience in programming or computer science can help you understand data structures better. Students are taught some of the basic and most common data structures in the beginning. They are also taught how to implement and use those data structures within a language.

While having some computer science knowledge is helpful in learning data structures, it’s certainly not necessary in the very beginning. As you begin to become more fluent and knowledgeable within the programming language you’re learning, you can start to gain an understanding of some of the more advanced implementations of data structures and algorithms.

Though, it must be noted that having a good understanding of data structures can help you have a better underlying understanding of the code you’re writing when you are learning a programming language and the impact your data will have on your program.

How to Learn Data Structures: Step-by-Step

Learning data structures takes time, dedication, and practice. It’s important to understand how to use data structures conceptually, as well as knowing how to use and implement them. Here are five steps you can take to learn data structures:

  1. Pick a programming language to use. While you can learn data structures conceptually, it might be easier to learn and understand data structures when used within a programming language. This can be a language you’re already familiar with, or you can start learning data structures while learning your first programming language. If you don’t already know a programming language, Python is always a good choice as your first. See Python Project Ideas for Beginners in 2020 .
  2. Select an in-person or online course to learn data structures. Data structures are the foundation of any computer science curriculum, they can also be learned as a self-learner or as a part of some coding bootcamps. Whether you’re deciding on pursuing a degree in computer science or learning elsewhere, there are endless resources available to learn data structures. Get matched with Top Bootcamps with FastTrack .
  3. Dedicate time for learning each day or week. The skill of understanding data structures takes a consistent amount of time to learn. As your schedule allows, dedicate an hour a night, or a few hours per week for uninterrupted learning.
  4. Practice what you’ve learned. Many experienced programmers will tell you practice is paramount to gaining a deep understanding of computer science concepts including data structures. To practice, you can start building a program of your own or you can complete code challenges that utilize data structures on sites such as Edabit , Code Signal , or HackerRank .
  5. Expand your knowledge to another language. After you feel confident, or even fluent in your first language, branch out and learn another. Compare and contrast how data structures are used in each language. While it’s not necessary to learn more than one programming language, sometimes learning a second language helps you understand both languages better. While data structures are seen and supported in many languages, their implementation or usage might be different depending on the language you’re using.

In-Person Instruction for Learning Data Structures

Check your nearby community college or local university if you’re interested in learning data structures. College courses that teach data structures might be part of a degree program in computer science, but your local institution may also teach certified courses. Some schools might also provide courses as part of a professional development or continued learning program.

Online Instruction for Learning Data Structures

It’s not necessary to seek a college degree to learn and utilize data structures within your code. Many successful computer scientists and programmers are self-taught, or have taken online computer science courses, or have attended online bootcamps. If online learning fits your learning style, here are some resources you can use to learn data structures online:

Data Structures Fundamentals is offered on edX by The University of California, San Diego and is taught by Daniel Kane and Alexander S. Kulikov. You are required to have a basic grasp of a common programming language such as C, Java, JavaScript, or Python (among others).

The course is self-paced and should take about six weeks to complete with an 8-10 hour per week time commitment. The course is offered free, but you can get a verified certificate for $99.

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This popular intro to computer science course is offered free online on edX and is provided by Harvard. While this course will teach you data structures, it goes more in-depth teaching by also teaching “algorithms, data structures, encapsulation, resource management, security, software engineering, and web development”.

CS50 is self-paced and takes 11 weeks to complete with a 10-20 hour per week commitment. There are no prerequisites required to take CS50, and the class is a part of several professional certificate programs available. You can get a verified certificate for $199 after completing this course.

Open Data Structures is an open context textbook found online. Learning from the website is free, and an optional paid paperback version available on Amazon.  Open Data Structures provides learning data structures in three programming languages (Python, Java, and C++) and five human languages (English, Slovenian, Turkish, Japanese, and Portugese).

Data Structures Books

There are many books available to learn data structures. Whether it’s a digital book or a physical copy, having a book with you while you learn is a great resource to gain a solid understanding of data structures.

‘A Common-Sense Guide to Data Structures and Algorithms, Second Edition: Level Up Your Core Programming Skills’ , by Jay Wengrow

Offered as an ebook or paperback, this book offers a practical approach to mastering data structures and algorithms so your mobile and web applications run more efficiently. Code examples are provided in JavaScript, Python, and Ruby.

‘Hands-On Data Structures and Algorithms with Python, Second Edition’ , by Dr. Basant Agarwal and Benjamin Baca

This book allows you to learn data structures and algorithms in Python. You’ll learn data structures discussed in this article, as well as an assortment of sorting algorithms such as bubble sort and selection sort. You’ll also learn some Python coding best practices. This book assumes you have basic knowledge of Python before reading it.

‘Grokking Algorithms: An Illustrated Guide for Programmers and Other Curious People, 1st Edition’ , by Aditya Bhargava

While Grokking Algorithms focuses more on algorithms and less on data structures, reading this book makes it easy to see how algorithms are used on data structures and exactly what purpose they serve within your code. The examples in this book are easy to understand and will sometimes even make you LOL. This book is a must-read for everyone in the beginning of their quest for understanding data structures and algorithms.

Online Resources for Learning Data Structures

CS Dojo on YouTube

CS Dojo used to be a Software Developer at Google. He offers easy-to-understand videos on Computer Science topics and has a playlist dedicated to teaching Data Structures and Algorithms .

CS50 Lecture 5 – Data Structures on YouTube

This is the fifth lecture in the CS50 course mentioned in the online instruction section of this article. The almost two-hour course offers in-depth explanations of popular data structures and how to implement them.

Rob Edwards on YouTube

Rob Edwards is a microbiologist and computer programmer in Australia. Like CS Dojo, he has a YouTube channel full of videos on many computer science topics, as well as a playlist dedicated to data structures . His explanations and illustrations make data structures easier to understand.

GeeksforGeeks

GeeksforGeeks is a website dedicated to many computer science and programming topics. Their explanations and code examples are usually offered in a few different programming languages such as C++, Java, Python, C#, and PHP. This site is bookmark-worthy, as they are extremely helpful when learning about different topics along with hundreds of accompanying subtopics, explanations, and examples.

Here they go into different types of data structures, their use cases, and implementations of them.

Should You Study Data Structures?

If you’re on a quest to learn to code for more than just a hobby, learning data structures is a must. And even then, having a good foundation of data structures will help you write better, more performant code. They allow you to organize your code so data can be easily stored, accessed, and manipulated by the device a user is using.

Data structures are commonly used in professional programming environments and all professional programmers have at least some basic knowledge of data structures. Most job recruiters assume you have an understanding of data structures and will see how you utilize them during your coding interview. Level up your skills and knowledge by learning data structures and perhaps even some algorithms to go along with them.

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Brandi Taylor

About the author: Brandi Taylor is a technical writer at Career Karma, where she covers topics such as iOS development, computer science, and web development. A Lambda School alum, Brandi has been immersed in the tech world since the late 90s as a freelance web designer, building sites for startups and other organizations. Since joining the Career Karma team in November 2020, Brandi has used her extensive software development knowledge to connect people with future careers in tech.

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