This article will guide you through the structure of a Python program, explain how indentation and line breaks work, and show how to use comments effectively.
Structure of a Python Program
A typical Python program is made up of one or more lines of code that perform specific tasks. Each Python file is known as a script and usually follows this structure:# Step 1: Comments and Documentation
# This program prints a simple message
# Step 2: Import Statements
import math
# Step 3: Function Definition
def greet():
print("Hello, Python Learner!")
# Step 4: Main Program Execution
if __name__ == "__main__":
greet()
Key Points:
1. Comments help describe the purpose of the code.2. Import statements allow you to use external or built-in modules.
3. Functions help organize and reuse code.
4. The condition
if __name__ == "__main__": ensures that the code inside it runs only when the script is executed directly.5. This simple structure gives your Python program a logical flow that's easy to understand and maintain.
Indentation in Python
Unlike many programming languages that use braces{} or keywords to define blocks, Python uses indentation (spaces or tabs) to indicate code blocks.
if True:
print("This is indented correctly.")
print("Python uses indentation to define blocks.")
print() statements are part of the if block because they are indented equally.
If indentation is missing or inconsistent, Python will throw an error:
if True:
print("Missing indentation!") # ❌ IndentationError
Recommended Indentation Rule:
- Use 4 spaces per indentation level (PEP 8 standard).- Avoid mixing tabs and spaces. Stick to one method.
Proper indentation not only avoids errors but also improves code readability — a core principle of Python syntax.
Line Breaks in Python
In Python, each line typically represents a single statement. You can, however, split long lines or combine short ones using special symbols.1. Implicit Line Continuation
You can write long expressions inside parentheses(), brackets [], or braces {} without using any special symbol:
numbers = [
1, 2, 3, 4, 5,
6, 7, 8, 9, 10
]
2. Explicit Line Continuation
Use a backslash\ to break a line manually:
total = 10 + 20 + 30 + \
40 + 50
3. Multiple Statements on One Line
Use a semicolon; to write multiple short statements on the same line (though not recommended):
a = 10; b = 20; print(a + b)
Comments in Python
Comments are non-executable lines that help explain your code. They are ignored by the Python interpreter but are essential for documentation and readability.1. Single-Line Comments
Use the hash symbol # at the beginning of the line:# This is a single-line comment
print("Hello, Python!") # Inline comment
2. Multi-Line Comments
Although Python doesn’t have a built-in multi-line comment syntax, you can use triple quotes (''' or """) to create documentation-style comments:"""
This is a multi-line comment.
It can span across several lines.
Useful for explaining complex code.
"""
print("Multi-line comment example")
3. Docstrings (Documentation Strings)
Docstrings are special multi-line comments used to describe functions, classes, and modules. They can be accessed at runtime using the .__doc__ attribute.def add(a, b):
"""This function returns the sum of two numbers."""
return a + b
print(add.__doc__)
Output:
This function returns the sum of two numbers.
Summary
Python's focus on clean syntax, readable indentation, and meaningful comments makes it one of the most elegant programming languages.In the next article, we'll explore Variables and Data Types in Python — the foundation of storing and manipulating data effectively.
