Python Variables - Step-by-Step Guide

🐍Python Variables – A Complete Beginner's Guide (Step-by-Step)

Let's learn variables in Python in the most basic, most beginner-friendly manner possible — with examples, rules, and actual use cases. Whether you're a beginner or refreshing your basics, this tutorial will assist you in creating a strong foundation.

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📦 What is a Variable in Python?

In Python, a variable is just a label that refers to a value in memory.
You can imagine it as a labeled box that holds some data.

Here's an example:

x = 10

In this situation:

• x is the variable name (the label)
• 10 is the value that is being stored (the content of the box)

Python knows automatically that 10 is an integer — no type declaration needed!

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🔤 How to Declare a Variable in Python

The syntax to declare a variable is simple:

variable_name = value

Examples:

name = "Nivesh"
age = 21
pi = 3.14
is_student = True

As you can notice, Python allows you to store text, numbers, decimals, and even Boolean values in variables.

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✅ Rules for Naming Variables in Python

When defining variables, use these easy rules:

1. Variable names should start with a letter (A–Z or a–z) or an underscore `_`
2. They may contain numbers after the first character
3. You cannot use Python keywords such as if, for, class, while, etc.
4. Variable names are case-sensitive (e.g., Age and age are different)

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🧪 Valid and Invalid Examples of Variable Names

✅ Valid:

name = "Krishna"
_age = 30
num1 = 100

❌ Invalid:

# 1num = 50     → Begins with a number
# for = "loop"  → "for" is a reserved keyword

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🧠 Python is Dynamically Typed

Python is a dynamically typed language, meaning you don't have to tell Python what type a variable is when you declare it. Python determines it for you.

x = 5         # x is an integer
x = "hello"   # Now x is a string
x = 3.14      # Now x is a float

Yes — you can assign various types of values to the same variable!

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📋 Variable Types in Python

Here's a handy reference of general data types you can hold in variables:

Type	Example
int	x = 5
float	pi = 3.14
str	name = "A"
bool	is_ok = True
list	nums = [1, 2]
tuple	t = (1, 2)
dict	d = {"a": 1}

Each of these types is useful in different scenarios — and we’ll explore them in future lessons.

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🔄 Assigning Multiple Values

Python allows assigning values to multiple variables in a single line:

a, b, c = 1, 2, 3

You can also assign the same value to multiple variables at once:

x = y = z = 100

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📤 Displaying Variable Output

You can use the print() function to display the value of a variable.

name = "Radha"
print("Hello", name)

Output:

Hello Radha

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🔐 Best Practices for Naming Variables

To write clean and readable Python code, follow these guidelines:

• ✅ Use descriptive names: total_price is preferred over tp
• ✅ Use lower case with underscores (snake_case): my_name, student_marks
• ❌ Don't use single-letter names unless in short loops (i, j, etc.)
• ❌ Avoid using cryptic or ambiguous names such as x1, temp123, etc.

💻 Stay tuned, and keep coding!

Python Variables (Step-by-Step Guide)