match — Intermediate Examples

Begins a structural pattern matching block (3.10+)

EasyIntermediateAdvancedExpert

Destructuring patterns

Matching and extracting data from structures.

python
# Sequence patterns
point = (3, 4)
match point:
    case (0, 0):
        print("Origin")
    case (x, 0):
        print(f"On x-axis at {x}")
    case (0, y):
        print(f"On y-axis at {y}")
    case (x, y):
        print(f"Point at ({x}, {y})")

# Mapping patterns
config = {"type": "circle", "radius": 5}
match config:
    case {"type": "circle", "radius": r}:
        print(f"Circle with radius {r}, area = {3.14 * r**2:.1f}")
    case {"type": "rectangle", "width": w, "height": h}:
        print(f"Rectangle {w}x{h}, area = {w*h}")

# Nested patterns
data = {"user": {"name": "Alice", "role": "admin"}}
match data:
    case {"user": {"name": str(name), "role": "admin"}}:
        print(f"Admin: {name}")
    case {"user": {"name": str(name)}}:
        print(f"User: {name}")
Expected Output
Point at (3, 4)
Circle with radius 5, area = 78.5
Admin: Alice

match can destructure sequences, mappings, and nested structures. Capture variables extract values from the matched structure.

Guard clauses in match

Adding conditions to case patterns.

python
# Guards with 'if'
def classify(value):
    match value:
        case int(n) if n < 0:
            return "negative integer"
        case int(n) if n == 0:
            return "zero"
        case int(n) if n > 0:
            return "positive integer"
        case float(f) if f != f:  # NaN check
            return "NaN"
        case float(f):
            return f"float: {f}"
        case str(s) if len(s) == 0:
            return "empty string"
        case str(s):
            return f"string: {s!r}"
        case _:
            return f"other: {type(value).__name__}"

for v in [-5, 0, 42, 3.14, float("nan"), "", "hello", [1]]:
    print(f"  {v!r:>10} -> {classify(v)}")

Guards (if clauses) add conditions to case patterns. The pattern must match AND the guard must be True for the case to execute.

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