Python Pattern Matching

# Python Pattern Matching - Interactive Examples
# Learn match statements through hands-on practice (Python 3.10+)
# === DATA STRUCTURE MATCHER ===
# Example of pattern matching with different data types
data = null
match data:
    case []:
        result = "Empty list detected"
    case [single]:
        result = `Single item list: ${single}`
    case [first, second]:
        result = `Two items: ${first}, ${second}`
    case [first, *rest]:
        result = `First: ${first}, Rest: ${len(rest)} items`
    case (0, 0):
        result = "Origin point detected"
    case (x, 0) if x > 0:
        result = "Positive X-axis point"
    case (0, y) if y > 0:
        result = "Positive Y-axis point"
    case (x, y):
        result = `Point at (${x}, ${y})`
    case _:
        result = "Unknown data type"
print(f"Data pattern result: {result}")
# === COMMAND PARSER ===
# Example of literal pattern matching
command = "help"
match command.lower().split():
    case ["start"]:
        action = "Starting system"
    case ["start", *args]:
        action = `Starting ${' '.join(args)}`
    case ["stop"]:
        action = "Stopping system"
    case ["restart"]:
        action = "Restarting system"
    case ["list", target]:
        action = `Listing ${target}`
    case ["delete", *items] if items:
        action = `Deleting: ${' '.join(items)}`
    case ["help"]:
        action = "Showing help"
    case _:
        action = "Unknown command"
print(f"Command result: {action}")
# === SHAPE CLASSIFIER ===
# Example of pattern matching with guards and object patterns
shape = {"type": "none", "properties": {}}
match shape:
    case {"type": "circle", "properties": {"radius": r}} if r > 10:
        classification = "Large Circle"
        area = 3.14159 * r ** 2
    case {"type": "circle", "properties": {"radius": r}}:
        classification = "Small Circle"
        area = 3.14159 * r ** 2
    case {"type": "square", "properties": {"side": s}} if s > 10:
        classification = "Large Square"
        area = s ** 2
    case {"type": "square", "properties": {"side": s}}:
        classification = "Small Square"
        area = s ** 2
    case {"type": "triangle", "properties": {"base": b, "height": h}}:
        classification = "Triangle"
        area = 0.5 * b * h
    case {"type": "polygon", "properties": {"sides": n}} if n > 6:
        classification = "Complex Polygon"
        area = None  # Complex calculation needed
    case _:
        classification = "Unknown Shape"
        area = None
print(f"Shape: {classification}, Area: {area}")
# Key Pattern Matching Concepts:
# - Literal patterns: case "start":
# - Variable capture: case [first, *rest]:
# - Guard conditions: case x if x > 10:
# - Object patterns: case {"type": "user", "name": name}:
# - Wildcard pattern: case _:
# - Multiple patterns and complex matching