Structural pattern matching in Python

match/case: branching on the shape of data, not just its value.

def describe(command):
    match command.split():
        case ["go", direction]:
            return f"walking {direction}"
        case ["look"]:
            return "you see a wall of code"
        case ["take", *items]:
            return f"picked up {len(items)} items"
        case _:
            return "unknown command"


print(describe("go north"))
print(describe("take sword shield"))

How it works

1. Each case tries to fit the split command list.
2. Patterns capture parts into names like direction.
3. *items matches a variable-length tail.
4. case _ is the catch-all fallback.

Keywords and builtins used here

• _
• case
• def
• describe
• len
• match
• print
• return

The run, in numbers

Lines

14

Characters to type

308

Tokens

88

Three-star pace

90 tpm

At the three-star pace of 90 tokens a minute, this run takes about 59 seconds.

Type this snippet

Step 4 of 7 in Flow control, step 19 of 72 in Language basics.

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