case — Advanced Playground

Defines a pattern branch inside a match statement (3.10+)

Python Playground

# Simulating exhaustive matching
from enum import Enum

class Color(Enum):
    RED = 1
    GREEN = 2
    BLUE = 3

def describe_color(c):
    match c:
        case Color.RED:
            return "Warm color"
        case Color.GREEN:
            return "Cool color"
        case Color.BLUE:
            return "Cool color"
        # No wildcard - if a new variant is added,
        # this will return None (implicit)

for c in Color:
    print(f"{c.name}: {describe_color(c)}")

# Case with walrus-like capture
data = {"type": "user", "name": "Alice", "age": 30, "role": "admin"}
match data:
    case {"type": "user", "name": str(name), **rest}:
        print(f"User {name}, extra fields: {rest}")

Output

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Use ** in mapping patterns to capture remaining keys. For exhaustive matching with enums, omit the wildcard so that missing cases return None (or add explicit error handling).

Challenge

Try modifying the code above to explore different behaviors. Can you extend the example to handle a new use case?

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