Conditionals (if / elif / else)

Introduction

Python conditionals use if, elif, else with colons and indented blocks. Python 3.10+ adds match-case for structural pattern matching.

Understanding the topic

Core concepts to understand:

• elif chains avoid nested ifs.
• Ternary: x if cond else y.
• Truthy/falsy: empty collections, 0, None, '' are falsy.
• match-case (3.10+) for pattern matching.

Syntax reference

Visual flow / code:

score = 85
if score >= 90:
    grade = "A"
elif score >= 80:
    grade = "B"
else:
    grade = "C"

# Ternary
status = "pass" if score >= 60 else "fail"

# match-case (3.10+)
match status:
    case "pass": print("🎉")
    case "fail": print("😢")
    case _: print("?")

Execution workflow

Real-world use

Pattern matching with match is now standard in modern Python codebases — especially for handling API responses, state machines, and parsing.

Best practices

• Use elif over nested ifs.
• Exploit truthy/falsy for cleaner checks.
• Prefer match-case for multi-branch dispatch.

Common mistakes

• if x == True: is redundant — just if x:.

Hands-on exercise

Interview preparation — practice these questions:

• What's truthy/falsy?
• What's match-case?
• How does ternary work?

Summary

In summary: elif chains > nested ifs. match-case for modern dispatch.