Conditional Statements in Python: A Beginner’s Guide

Control flow is the backbone of any programming language, and in Python, the if-elif-else statement is your go-to tool for making decisions in code. Whether you're building a simple calculator or a complex machine learning pipeline, you'll find yourself using these conditional statements all the time.

In this post, we’ll break down how if, elif, and else work in Python, with clear examples and best practices.

What Are Conditional Statements?

Conditional statements allow your program to make decisions based on certain conditions. Think of them as the logic gates of your code: "If this is true, do that. Otherwise, do something else."

The Basic Structure

if condition1:

    # Code block executed if condition1 is True

elif condition2:

    # Code block executed if condition1 is False and condition2 is True

else:

    # Code block executed if none of the above conditions are True

You can have:

• Just an if

• An if with one or more elifs

• An if with an else

• Or all three together

Example 1: Simple Age Check

age = 20

if age < 18:

    print("You are a minor.")

elif age < 65:

    print("You are an adult.")

else:

    print("You are a senior citizen.")

Output

You are an adult.

How Python Evaluates Conditions

Python checks each condition from top to bottom:

• As soon as it finds a True condition, it executes that block and skips the rest.

• If none of the conditions are True, it runs the else block (if present).

Indentation Matters!

Python uses indentation (usually 4 spaces) to define blocks of code. Forgetting to indent properly will raise an IndentationError.

if True:

print("This will cause an error!")  # Wrong indentation

Example 2: Grading System

score = 85

if score >= 90:

    print("Grade: A")

elif score >= 80:

    print("Grade: B")

elif score >= 70:

    print("Grade: C")

else:

    print("Grade: F")

Output

Grade: B

Best Practices

• Keep conditions simple and readable.

• Use parentheses for clarity in complex conditions.

• Avoid deeply nested if statements—consider using functions or dictionaries for cleaner logic.

Bonus: Using Logical Operators

You can combine conditions using and, or, and not.

temperature = 25

humidity = 60

if temperature &gt; 20 and humidity &lt; 70:

    print("Nice weather!")

Conclusion

The if-elif-else structure is one of the most fundamental tools in your Python toolkit. Mastering it will help you write smarter, more responsive programs.

Next up in the series: Loops in Python – for and while explained!