Python Variables (with Examples)

🐍 Python Variables: The Cool Kid’s Guide 🎩

Welcome to the world of Python variables — where data gets stored, changed, juggled, and sometimes even misplaced (oops). Think of a variable as your pet jar that holds jellybeans (or maybe integers, strings, lists...).

In this epic journey, you’ll learn the essentials of variables, naming rituals, the mystery of scopes (local vs. global), and a few sorcerer-level tricks like chained assignments. Buckle up!

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🏷️ 1. Python Variable Naming Convention

Before you name your variable GandalfTheGray, there are a few sacred scrolls (rules) you should honor:

• 🥇 Must start with a letter (a-z, A-Z) or an underscore (_).
• 🔢 Can include letters, numbers, and underscores (party mix).
• 🔠 Case-sensitive! myVariable ≠ myvariable.
• 🚫 Avoid using Python’s holy reserved words like if, for, while, etc.
• 🌐 Unicode is welcome! You can name a variable π or 名字 if that’s your jam.

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🧪 2. Declaring a Variable in Python

Python is chill — you don’t have to scream the data type like in other languages. Just throw a value at a name, and boom 💥 — you’ve got a variable.

🎯 2.1 Simple Variable Assignments

# Assigning an integer value to a variable
age = 25

# Assigning a string value to a variable
name = "Alice"

# Assigning a list of numbers to a variable
scores = [90, 85, 88, 92]

Wanna be fancy?

author = 'Sujit'
blogName = "FOSS GURU"

Single or double quotes — your choice. Python isn’t picky like some people on dating apps.

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🔗 2.2 Chained Assignments

Want to clone a value across multiple variables like a boss? Do this:

i = j = k = 20

print(i)  # prints 20
print(j)  # prints 20
print(k)  # prints 20

Now all your variables are twins. Or triplets. Or quadruplets. You get the idea.

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🧙‍♂️ 2.3 Declaring Multiple Variables in One Line

Why write three lines when one will do?

x, y, z = 10, 20, 30

print("x:", x)
print("y:", y)
print("z:", z)

Perfect for when you're unpacking a treasure chest (aka list/tuple) 🧳

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🔁 2.4 Variable Re-declaration

Python’s flexible. Today index is a number, tomorrow it’s a string. Who are we to judge?

index = 10
index = 20
index = "NA"  # index is now a string variable

print(index)  # prints NA

You can change its type faster than a cat changes its mind.

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🧠 3. Local vs Global Variables

A tale of two kingdoms: Localandia and Globalopolis. 🎭

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🏠 3.1 Local Variable

Born and raised inside a function. They don’t know what the outside world looks like.

def my_function():
    x = 10
    print("Inside the function, x =", x)

my_function()

Outside the function? x is a ghost. 👻

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🌍 3.2 Global Variable

This is your loud neighbor who shows up everywhere.

y = 20

def my_function():
    global y
    print("Inside the function, y =", y)
    y = 30  # changing the neighborhood!

my_function()
print("Outside the function, y =", y)

Output:

Inside the function, y = 20
Outside the function, y = 30

⚠️ Best Practice Tip: Avoid modifying globals like it’s a buffet. Keep them sacred unless you really must.

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🔥 4. Variable Examples You’ll Actually Use

Let’s do some real-life wizardry 🧙

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🧮 4.1 Calculating Area of a Rectangle

length = 10
width = 5
area = length * width

print("The area of the rectangle is:", area)

Yup, we’re all architects now 🏗️

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🧩 4.2 Concatenating Strings

first_name = "John"
last_name = "Doe"
full_name = first_name + " " + last_name

print("Full Name:", full_name)

Now go build your very own name generator 💡

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🍎 4.3 Working with Lists

fruits = ["apple", "banana", "cherry"]
print("Second fruit:", fruits[1])
fruits.append("orange")
print("Updated list of fruits:", fruits)

Python lists: Your digital fruit basket 🧺

❓ Drop Your Variable Questions

Got doubts? Confusions? Existential crises related to variables? Hit me up!

Happy Learning & May Your Variables Always Be Bug-Free! 🚀🐍