Python Syntax, Variables and Data Types

What You’ll Learn in This Blog

• Python syntax rules
• How to declare and use variables
• Core data types: int, float, str, bool
• Type casting and dynamic typing
• Best practices with examples

What is Python Syntax?

Python's syntax is known for being clean, minimal, and easy to understand.

Basic Rules

• Python uses indentation instead of braces {} to define code blocks.
• A line of code ends with a newline (not semicolons like in C/C++).
• Comments start with #.

Example:

# This is a comment
name = "Akash"
if name == "Akash":
    print("Welcome Akash!")  # Indentation is required

Variables in Python

What is a Variable?

A variable is a name that holds a value.

In Python, you don't need to declare the type explicitly. Just assign:

x = 10
name = "Akash"

Naming Rules

• Can contain letters, digits, and underscores (_)
• Must start with a letter or underscore
• Case-sensitive (Name≠ name)
• Don't use Python keywords (if, for, etc.)

Python Data Types

1. Integer (int)

age = 25
print(type(age))  # Output: <class 'int'>

2. Floating Point (float)

pi = 3.14
print(type(pi))  # Output: <class 'float'>

3. String (str)

greeting = "Hello"
print(type(greeting))  # Output: <class 'str'>

4. Boolean (bool)

is_active = True
print(type(is_active))  # Output: <class 'bool'>

Type Casting in Python

You can convert between types using:

int("5")         # Converts string to int
float("2.5")     # Converts string to float
str(100)         # Converts int to string
bool(1)          # Converts int to bool (1 = True)

Example:

x = "100"
y = int(x) + 50
print(y)  # Output: 150

Python is Dynamically Typed

You don’t need to declare variable types:

a = 5        # int
a = "Hello"  # now a string

This makes Python flexible, but you should still use consistent naming and typing.

Python Variable Tricks

Multiple assignments:

x, y, z = 1, 2, 3

Swap two variables:

a, b = 10, 20
a, b = b, a

Constants (by convention):

PI = 3.14  # all caps indicate constant

Best Practices

• Use snake_case for variable names: user_name
• Use descriptive names: count, user_email
• Comment where necessary
• Stick to one naming style across your project

Summary

Task

1. Create a program that asks the user for their name and age, then prints:

Hello Akash! You are 25 years old.

2. Try assigning different data types to a variable and print their types using type().