3. Basic Syntax and Data Types

What Is Syntax?

Syntax is simply the set of rules a programming language follows. Just like grammar in English helps us form sentences, syntax helps us write valid code Python can understand.

Python Comments

Comments help you describe what your code does. Python ignores them when running your program. Use them as notes for yourself or others.

# This is a single-line comment
print("Hello!")  # You can also comment beside a line

"""
This is a multi-line comment.
Useful for documentation.
"""

Variables in Python

Variables store values in Python. You don’t need to declare types — Python figures that out automatically.

name = "Ada"
age = 25
height = 5.4
is_student = True

• Variables must start with a letter or underscore
• They are case-sensitive (`Name` and `name` are different)
• Use snake_case naming like total_price or user_name

Python Data Types

These are the basic data types we’ll start with:

Using type()

You can check what type of data a variable holds using the type() function.

print(type("Hello"))  # <class 'str'>
print(type(42))       # <class 'int'>
print(type(3.14))     # <class 'float'>
print(type(True))     # <class 'bool'>

Rules of Python Syntax

• Python uses indentation instead of curly braces
• Every indentation is usually 4 spaces
• No semicolons needed at the end of statements
• Case matters (`Print` is not `print`)

Common Syntax Mistakes

• IndentationError: Incorrect spacing
• SyntaxError: Missing quotes or parenthesis
• NameError: Using a variable before defining it

Mini Project Step

Create a new file called profile.py and declare variables to store your name, age, country, and a fun fact about yourself. Then print them in a sentence.

name = "Chrise"
age = 21
country = "Nigeria"
is_learning_python = True

print(name, "from", country, "is learning Python:", is_learning_python)

Python Official Data Types Guide