Interview question

What are common built-in decorators like @staticmethod, @classmethod, and @property? @staticmethod, @classmethod, @property जैसे common built-in decorators क्या हैं?

Answer

Decorator	First parameter	Called on	Purpose
@staticmethod	None - no automatic self/cls	Class or instance	Utility function logically grouped in the class
@classmethod	cls (the class itself)	Class or instance	Alternative constructors, class-level operations
@property	self	Instance (accessed like an attribute)	Computed/read-only attributes

class Pizza:
    def __init__(self, radius, toppings):
        self.radius = radius
        self.toppings = toppings

    # Regular instance method - needs self, operates on instance data
    def area(self):
        return 3.14159 * self.radius ** 2

    # staticmethod - no access to self or cls, just grouped logically here
    @staticmethod
    def is_valid_topping(topping):
        return topping in ['cheese', 'pepperoni', 'mushroom']

    # classmethod - alternative constructor pattern
    @classmethod
    def margherita(cls):
        return cls(radius=12, toppings=['cheese', 'tomato'])

    # property - accessed like an attribute, computed on the fly
    @property
    def diameter(self):
        return self.radius * 2

pizza = Pizza(10, ['cheese'])
print(pizza.area())               # instance method - needs ()
print(Pizza.is_valid_topping('cheese'))  # static - called on class directly

margherita = Pizza.margherita()   # classmethod - alternative constructor
print(margherita.toppings)        # ['cheese', 'tomato']

print(pizza.diameter)             # property - NO parentheses, accessed like attribute

Decorator	पहला parameter	कैसे call होता है	उद्देश्य
@staticmethod	कोई नहीं	Class या instance	Class में logically grouped utility
@classmethod	cls	Class या instance	Alternative constructors
@property	self	Instance (attribute की तरह)	Computed/read-only attributes

class Pizza:
    def __init__(self, radius, toppings):
        self.radius = radius
        self.toppings = toppings

    def area(self):
        return 3.14159 * self.radius ** 2

    @staticmethod
    def is_valid_topping(topping):
        return topping in ['cheese', 'pepperoni', 'mushroom']

    @classmethod
    def margherita(cls):
        return cls(radius=12, toppings=['cheese', 'tomato'])

    @property
    def diameter(self):
        return self.radius * 2

pizza = Pizza(10, ['cheese'])
print(pizza.area())
print(Pizza.is_valid_topping('cheese'))

margherita = Pizza.margherita()
print(margherita.toppings)

print(pizza.diameter)  # parentheses नहीं, attribute की तरह

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