In this blog, we will learn what variables and data types are in Python, why they are important, and how to practice them with a small bioinformatics project at the end.

But first, tell me how you are feeling after writing your first Python code? I hope it gave you confidence and motivation. If you haven’t seen my first blog on running your first Python code, check it here.

What Are Variables and Data Types in Python?

Have you ever called someone by their name? Of course — we all do.
Now imagine if you had no name. How would people identify you? It is our names that make us unique.

The same idea applies to Python variables.
Variables in Python are like names or labels we assign to data types (like numbers, text, or sequences) so we can store and access them easily later.

Example with simple data:

container1 = 'Qurat'
container2 = 'blogger'

Here, container1 and container2 are variables (labels).
Whenever I want to access 'Qurat'. I can simply call container1 instead of typing 'Qurat' again.

Understanding Variables with Bioinformatics Example

Now let’s relate it to bioinformatics, our core field!

Imagine you are working with DNA and RNA sequences.
Instead of copying long sequences repeatedly, you can store them in variables.

Example:

dna_sequence = 'ATCGTACGGA'
rna_sequence = 'AUCGAUCGGA'
gene_name = 'TP53'

• dna_sequence is a variable storing a DNA sequence.
• rna_sequence stores an RNA sequence.
• gene_name stores the name of a gene.

Now, anytime we want to analyze or manipulate these sequences, we just call their variable names!

Rules for Naming Python Variables

When assigning names to variables in Python (whether it’s simple data or biological data), follow these rules:

1. Variable names can contain letters, numbers, and underscores (_).
2. A variable cannot start with a number.
3. Variable names are case-sensitive — gene_name and Gene_name are different.
4. You cannot use reserved Python keywords like if, for, while, etc. (See here: Python keywords)

Valid examples:

a = 3
_data = 'Write here'
full_name = 'Qurat-ul-ain'
dna_seq1 = 'ATCG'

Invalid examples:

34name = 'invalid'    # starts with a number
for = 45              # reserved word
gene/name = 'TP53'    # contains /

What Is an Assignment Statement?

The assignment statement uses = to assign a value to a variable.

Example:

gene_name = 'TP53'

Here, gene_name is assigned the string 'TP53'.

Project of the Day

Now, it is time to apply what you’ve learned by practicing and completing the project.

Project Task:

1. Create 3 variables to store the following:
   – Your favorite gene name
   – A short DNA sequence
   – A short RNA sequence
2. Print all 3 variables.

After completing your practice, please feel free to send your solved project to my email. I will definitely review it and will provide a detailed response.

In the next blog, we’ll learn how to use Python’s input function and basic string formatting.

Keep learning and keep exploring!

Today, I will show you how to write your very first Python program, and yes, you can do it in under a minute.

Have you ever wondered how programmers type code with speed and confidence?

Well, they all start from this simple line of Python:

print('Hello World')

After learning this one line, your confidence might boost by 25%, and the remaining motivation will come with consistent practice.

A Quick Note:

If you haven’t installed Python yet or don’t know how to open a coding environment, check out the step-by-step guide for beginners here, where I guide you step-by-step (no stress, I promise).

Your First Python Program:

print('Hello World')

This is your first step toward a beautiful coding journey. Let’s break this line down into simple chunks:

What is the print() Function in Python?

print() is a built-in function in Python used to display a message on your screen.
Think of it like this:

“Hey Python, please display the message inside the quotes.”

When you run this line, Python reads it and prints only the message inside the quotes.

What Can You Write Inside print()?

You can write:

Text (e.g; print('Hello'))

Numbers (e.g. print(42))

Math expressions (e.g. print(5 + 3))

All of this should be inside the parentheses, and text must be inside quotes.

Breaking Down Your First Python Line:

1. What is ‘Hello World’?

This is the message you’re asking Python to display. You can replace it with any sentence you like. For example:

print("Hello, my name is Qurat-ul-ain. I write blogs about Python and help beginners start their coding journey.")

2. What Are () in Python?

These are called parentheses. You use them to pass information (called arguments) to a function.

3. What Are ‘ ‘ or ” ” (Quotation Marks)?

Quotation marks tell Python that what’s inside is text (also called a string), but it is not code.

What You Learned Today:

Project of the Day:

Question: How can you print your favorite quote in Python?

Ready to explore more? In upcoming blogs, we will dive into Variables and Data Types. You’ll learn how to store and manipulate different types of data in Python, which is fundamental for writing more exciting and advanced programs.

Keep learning and keep exploring!

“If you’re new to programming, you might also find our guide helpful: Programming is Not as Hard as You Think.”

This will help beginners overcome any fear of coding before diving into Python.

1. Why Python is a Beginner-Friendly Programming Language

One of Python’s biggest advantages is its clean and human-readable syntax. Unlike other programming languages, Python’s structure is intuitive and closely resembles English. For example:

print("Hello, World!")

This simple command prints text on the screen, making it easy for beginners to understand what’s happening without needing advanced knowledge.

2. Learn Python with Minimal Setup – Start Coding in Minutes

Python is incredibly easy to install and set up. It runs on Windows, macOS, and Linux, and you can even write Python code online without installation using platforms like:

• Google Colab
• Jupyter Notebook
• Replit

This makes Python accessible to beginners who want to start coding without technical complications.

“Before diving into Python, it’s essential to set up your coding environment properly. Check out my guide on How to Start Coding as a Beginner to get started with the right tools.

3. Strong Community Support for Learning Python

Learning Python is easier when you have access to a vast community of programmers willing to help. If you get stuck, you can find support on:

• Stack Overflow (stackoverflow.com)
• Reddit Python Community (reddit.com/r/learnpython)
• Python’s Official Documentation (docs.python.org)

With so many resources available, beginners never feel lost for long!

4. Rich Library Ecosystem – No Need to Reinvent the Wheel

Python provides thousands of pre-built libraries that make coding easier and more efficient. Instead of writing everything from scratch, you can use these libraries to save time.

• For Data Science: NumPy, Pandas, Matplotlib are very useful
• For Web Development: Flask, Django are very helpful
• For Bioinformatics: Biopython is most important and easy to use library

These libraries make Python a powerful tool for both beginners and experts.

5. Python is an Easy-to-Learn, Interpreted Language – Great for Debugging

Python is an interpreted language, meaning you can run your code line by line instead of compiling an entire program at once. This allows for immediate feedback and easy debugging, which is great for beginners.

For example, if there’s an error in your code, Python will point it out immediately, helping you learn from your mistakes faster.

6. Best Beginner-Friendly Development Tools for Python

Python offers many beginner-friendly Integrated Development Environments (IDEs), including:

• Thonny – Best for absolute beginners
• IDLE – Comes pre-installed with Python
• Jupyter Notebook – Great for interactive coding and data visualization

These tools provide an intuitive environment for learning, testing, and experimenting with Python code.

7. Clear and Easy-to-Understand Error Messages

Unlike some programming languages with cryptic error messages, Python provides clear and human-readable errors. For example:

print("Hello, World!"   # Missing closing parenthesis

Python will display: SyntaxError: unexpected EOF while parsing

This helps beginners understand what went wrong and how to fix it.

8. Tons of Learning Resources Available for Free

Python has a massive collection of free learning resources, including:

• Official Python Docs – docs.python.org
• W3Schools Python Tutorial – w3schools.com/python
• Python Crash Course (Books & Videos)
• YouTube tutorials – Hundreds of free courses

No matter your learning style, there’s a Python resource for you!

9. Beginner-Friendly Projects – Learn by Doing

Python allows beginners to quickly build small, fun, and useful projects such as:

A simple calculator 

A to-do list app

A random password generator 

A basic chatbot

By working on these projects, you gain hands-on experience that builds confidence. To access a collection of well-structured Python projects, you can visit my GitHub repository:

Python Projects from Beginner to Advanced Level

This repository provides step-by-step guidance, making it easy to understand and follow.

10. Easy Transition to Advanced Topics

Python is beginner-friendly, but it also scales well for advanced use cases. Once you master the basics, you can move on to:

Machine Learning & AI (TensorFlow, Scikit-Learn)

Web Development (Django, Flask)

Bioinformatics (Biopython)

Automation & Scripting (Automate boring tasks with Python)

With Python, you don’t need to switch languages as you advance in your career.

Final Thoughts – Why Python is the Best Choice for Beginners

Python is easy to learn, powerful, and widely used across industries. Whether you’re learning programming for fun, for a job, or for research, Python is the best place to start!

Ready to Start? Stay tuned for more Python tutorials tailored for beginners and bioinformatics applications. Let’s learn together!

Question for You:

What makes Python most appealing to you? Simplicity, community support, or something else? Drop your thoughts in the comments below! 

Related Blog Posts

1. Programming is Not as Hard as You Think – Learn why coding is easier than you might imagine!
2. How to Start Coding as a Beginner – Step-by-step guide on choosing a language and setting up your environment.