Pattern Matching (match-case)

In Python 3.10, developers got a modern feature called match-case (known as switch-case in Java/C++).

It is designed as a cleaner, more readable replacement for long, messy if-elif-else chains when you are comparing a single variable against exact matching values.

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1. Why match-case? (Messy elif vs Clean match-case)

Imagine checking a user's role on a website:

❌ Messy if-elif Chain:

role = "admin"

if role == "admin":
    print("Full Access Allowed")
elif role == "editor":
    print("Edit Access Allowed")
elif role == "viewer":
    print("Read Only Access")
else:
    print("Unknown Role")

✅ Clean match-case Replacement:

role = "admin"

match role:
    case "admin":
        print("Full Access Allowed")
    case "editor":
        print("Edit Access Allowed")
    case "viewer":
        print("Read Only Access")
    case _:
        print("Unknown Role")  # _ is the wildcard default (like else!)

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2. Key Features of match-case

1. case _: (Wildcard Default)
   The underscore (_) acts as a fallback else block. If none of the specific cases match, case _: runs.

2. case "B" | "C": (Multiple Matches / OR)
   The pipe symbol (|) allows matching multiple values in a single case!

grade = "B"

match grade:
    case "A":
        print("Excellent performance!")
    case "B" | "C":
        print("Good job, keep it up!")  # Matches B or C
    case "F":
        print("Work hard and try again.")
    case _:
        print("Invalid grade!")

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3. Shortcut: Inline if-else (Ternary Operator)

Sometimes you want to assign a value to a variable based on a simple check in a single line:

# Syntax: <value_if_true> if <condition> else <value_if_false>
marks = 45
result = "Pass" if marks >= 35 else "Fail"

print(result)  # Output: Pass

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Quick Summary

• match-case (Python 3.10+): Structural pattern matching syntax for comparing a variable against exact values.
• Wildcard Fallback (case _:): Runs as the default fallback when no other cases match.
• Or Patterns (|): Combine multiple possible matches in a single case line (e.g., case "B" | "C":).
• Ternary Operator: Clean inline one-line condition (value_if_true if condition else value_if_false).

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What's Next?

Congratulations on completing Module 5! Now that we know how to make decisions in code, let's learn how to repeat tasks automatically using Loops (for, while) in Module 6!