Learn Python programming

Embarking on your journey to learn Python programming can appear daunting at first. However, with a structured approach, transitioning from a complete beginner to an experienced Python programmer is not only possible but highly achievable. Discover essential Python programming tips and guide yourself towards becoming an expert Python programmer.

Eduardo Miranda
May 09, 2024

🕒 Estimated reading time: 6 minutes

Here is a structured pathway covering basic, intermediate, and advanced concepts, punctuated with practical examples to solidify the learning process. This comprehensive guide aims at molding you into a proficient Python programmer, touching upon the essential concepts and techniques that form the building blocks of Python programming.

Introduction to Python 🐍

Python is a versatile, high-level, interpreted programming language devised by Guido van Rossum and made available to the public in 1991.

Distinguished by its clear and readable syntax, Python encourages the development of elegant and efficient code, in line with its philosophy of simplicity and minimalism. This approach has made it extremely popular among developers, establishing it as a preferred choice for a wide range of applications, from web development to complex analytics in data science, to machine learning and automation of routine tasks.

Thanks to an active community and abundant educational resources, learning Python is accessible for beginners, while its powerful standard library and framework-rich ecosystem offer robust tools for seasoned professionals. Thus, Python establishes itself as an essential language in the world of programming, opening doors to innovation and success in various fields of technology.

Now, let's dive into the world of Python with some practical examples that are also available on Google Colab here 👨‍🔬.

Basic Python Concepts

Code comment

In programming, a code comment is a section of text in your code that is not executed by the computer. Comments are used to leave notes and explanations for yourself or other programmers, making the code easier to understand and maintain. There are several reasons to use comments, including explaining the purpose of a block of code, marking sections of a codebase, providing links to related resources, or temporarily disabling a piece of code during development.

In Python, there are two main types of comments: single-line comments and multiline comments.

Single-line Comments: These start with a hash sign (#) and extend to the end of the line. Anything after the # on that line is considered a comment and ignored during execution.

Example:

# This is a single-line comment in Python

x = 5  # This is an inline comment explaining the line of code

Multiline Comments: Strictly speaking, Python doesn't have a specific syntax for multiline comments as some other languages do. However, triple-quoted strings (""" """ or ''' ''') are often used as a workaround because they can span multiple lines and Python does not execute them unless they are part of a statement (like in a docstring). It's important to note that these are technically not comments, but they are used as such to provide larger explanatory notes or disable chunks of code.

Example:

"""
This is a multiline comment used to describe the
following block of code. It explains what the code does
and why it's written the way it is. Though technically,
these are triple-quoted strings, not actual comments.
"""

print("Hello, World!")

When using comments, it's essential to strike a balance. Good code should be as self-explanatory as possible, with comments serving to clarify complex logic or decisions that aren't immediately apparent from the code itself. Over-commenting can make the code cluttered and harder to read, while under-commenting can leave others (or yourself in the future) puzzled about the purpose and functionality of certain code blocks.

Variables

Variables, Data Types, and Operators Variables are basic containers for storing data in Python. They could be likened to boxes where we keep our things for easy identification and access.

# Assign the string "John Doe" to the variable `name`
# - Variables in Python can store data of different types, such as strings.
# - Here, `name` acts as a label to access the string "John Doe".
# - Strings in Python are sequences of characters enclosed in quotes.
name = "John Doe"

# Assign the integer 30 to the variable `age`
# - Variables can also store numerical values, such as integers.
# - In this line, the variable `age` is used to represent a person's age, which is a whole number, thus an integer is used.
# - No quotes are used for integers; quotes are only for strings.
age = 30

Additional Explanation

In Python, a variable is created the moment you first assign a value to it. Variables do not need to be declared with any particular type, and can even change type after they have been set.

String: This is one of the built-in data types in Python used to store textual data. It's important to note that Python strings are immutable, meaning once a string is created, the elements within it cannot be changed.
Integer: This is another fundamental data type in Python intended to represent whole numbers. Python supports various numerical types (int for integers, float for floating-point numbers, complex for complex numbers).

Variables in Python are very flexible and allow you to store all types of data. They are essentially labels that point to the memory location where the data is stored. This makes retrieving or modifying the data easier as you use the program.

Data Types

Data types in Python include integers, floats, strings, and booleans. These types represent numbers, textual data, and true/false values, respectively.

Operators are symbols that perform operations on variables and values. For understanding, let’s perform a basic arithmetic operation:

# This Python script demonstrates the basic operation of adding two integers together and then printing the result to the console.

# The following line performs an addition operation.
sum = 5 + 10  # Result of addition is 15, and is stored in 'sum'

# Once the calculation is done and the result is stored in 'sum', the next line comes into play.
# The 'print()' function outputs whatever is inside its parentheses to the console.
# In this case, it will print out the value stored in the variable 'sum'.
print(sum)  # This will output: 15

Additional Explanation

The line sum = 5 + 10 performs an addition operation. It adds two integer values together, which are 5 and 10 in this case. The result of this addition, which is 15, will be stored in the variable named 'sum'.

⚠️ It's important to note that 'sum' is also the name of a built-in Python function. Overriding it in this case is generally considered bad practice as it can lead to confusion and errors in more complex programs. It's better to choose a variable name that doesn't conflict with the names of built-in functions. Examples could be 'total', 'result', or even 'sum_result'.

Once the calculation is done and the result is stored in 'sum', the next line comes into play. The 'print()' function is used here. This function outputs whatever is inside its parentheses to the console. In this case, it will print out the value stored in the variable 'sum'. Seeing as we previously calculated that 5 + 10 equals 15 and stored that result in 'sum', executing this line will print '15' to the console.

It's good practice to ensure your code is easily understandable by others by choosing clear variable names and providing comments where necessary, especially in cases where the operation or logic being performed might not be immediately clear.

Project in Action: From Theory to Practice

Now it's time to solidify your knowledge through practical application. Here's a simple example of a sum calculator written in Python, designed to accept two numbers from the user and then calculate their sum. Throughout the code, we provide comments to explain each part of the process, making it easy to follow and learn from.

A Simple Calculator

This code begins by defining a function add_numbers, which simply adds any two numbers it's given. Then, in the main function, it prompts the user to enter those two numbers, calling upon add_numbers to compute their sum. Finally, it prints out the result.

By running this script, the user will be prompted to enter two numbers, and the script will respond by displaying the sum of these numbers. This basic structure introduces important Python concepts like functions, input/output operations, and type conversion, making it a good starting point for beginners.

# Simple Sum Calculator in Python

print("Welcome to the Simple Sum Calculator!")

# Asking the user to input the first number. We use float to allow decimal numbers.
num1 = float(input("Enter the first number: "))

# Asking the user to input the second number
num2 = float(input("Enter the second number: "))

# Calculating the sum by calling the add_numbers function
sum_of_numbers = num1 + num2

# Displaying the result
print(f"The sum of {num1} and {num2} is {sum_of_numbers}")

Conclusion

We hope you enjoyed this introduction to Python. Whether you're a beginner eager to learn the basics or an intermediate programmer looking to deepen your knowledge, Python has something to offer. Remember, the learning journey is ongoing, and with practice and patience, you'll be creating amazing, complex programs in no time.

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Remember, the key to mastery is practice and persistence. Happy coding! Until the next edition, keep programming! 👨‍💻

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