Now, before we dive into this exciting world of variables and their magical powers, let me just clarify one thing: if you’re new to programming or haven’t heard about variables yet, don’t worry! We’ve got your back. In fact, we’ll be using some pretty basic examples throughout this article so that everyone can follow along easily.

So what exactly is variable substitution in Python? Well, it’s the process of replacing a placeholder (or “variable”) with its actual value when you run your code. For example:

# Define a variable called 'name' and assign it the string 'John Doe'
# Variable 'name' is created and assigned the string value 'John Doe'
name = 'John Doe'

# Print out the value stored in the 'name' variable using f-strings (Python 3.6+)
# The value stored in the 'name' variable is printed using f-strings, which allow for string interpolation
print(f"Hello, {name}!")

In this example, we first define a variable called `name` and assign it the string “John Doe”. Then, when we print out our message using an f-string, Python automatically replaces the placeholder (i.e., `${name}`) with its actual value (“John Doe”).

But wait there’s more! Variable substitution can also be used to perform calculations and manipulate data in your code. For example:

# Define two variables called 'x' and 'y', respectively, with values of 5 and 10
x = 5 # Assigns the value of 5 to the variable 'x'
y = 10 # Assigns the value of 10 to the variable 'y'

# Calculate the sum of these two numbers using variable substitution (i.e., x + y)
result = x + y # Assigns the sum of 'x' and 'y' to the variable 'result'

# Print out the result to the console
print(f"The sum of {x} and {y} is: {result}") # Prints out a message using an f-string, with the values of 'x', 'y', and 'result' substituted in the placeholders.

In this example, we first define two variables called `x` and `y`, respectively, with values of 5 and 10. Then, when we calculate the sum using variable substitution (i.e., `x + y`), Python automatically replaces these placeholders with their actual values (i.e., 5 and 10) before performing the calculation. Finally, we print out our result to the console using an f-string.

It might seem like a small thing at first glance, but trust us: once you start using this feature more frequently, you’ll wonder how you ever lived without it.