Control Flow

Advanced Match Patterns

match patterns can destructure sequences, combine alternatives, and add guards.

Sequence patterns match by position. A guard after if adds a condition that must also be true.

Source

def describe(command):
    match command:
        case ["move", x, y] if x >= 0 and y >= 0:
            return f"move to {x},{y}"
        case ["quit" | "exit"]:
            return "stop"
        case ["echo", *words]:
            return " ".join(words)
        case _:
            return "unknown"

print(describe(["move", 2, 3]))

Output

move to 2,3

An OR pattern accepts several alternatives in one case. A star pattern captures the rest of a sequence.

Source

print(describe(["exit"]))
print(describe(["echo", "hello", "python"]))

Output

stop
hello python

The wildcard _ catches values that did not match earlier cases. Here the guard rejects the negative coordinate.

Source

print(describe(["move", -1, 3]))

Output

unknown

Notes

Use case _ as a wildcard fallback.
Guards refine a pattern after the structure matches.
OR patterns and star patterns keep shape-based branches compact.

Run the complete example

Expected output

move to 2,3
stop
hello python
unknown

Execution time appears here after you run the example.

Advanced Match Patterns

See also

Run the complete example

Example code

Expected output