如何使用类方法与静态方法

class Date:
    """方法一：使用类方法"""  """达到多个构造函数"""
    # Primary constructor
    def __init__(self, year, month, day):
        self.year = year
        self.month = month
        self.day = day
    # Alternate constructor
    @classmethod #可以直接除了使用 __init__() 方法外，还有其他方式可以初始化它。
    def today(cls): # 不传参
        t = time.localtime()
        return (t.tm_year, t.tm_mon, t.tm_mday)
print(Date.today()) # 类调用
# (2022, 1, 2)
class newDate(Date):  # 可以继承
    pass
print(newDate.today()) #
# (2022, 1, 2)

class Book(object):
    def __init__(self, title):
        self.title = title
    @classmethod
    def create(cls, title):
        book = cls(title)  # 传参数必须转化
        return book
book1 = Book("python")
book2 = Book.create("python and django")
print(book1.title)
print(book2.title)

类方法调用静态方法，可以让cls代替类，静态调用静态方法

class Foo(object):
    X = 1
    Y = 2
    @staticmethod
    def averag(*mixes):
        return sum(mixes) / len(mixes)
    @staticmethod
    def static_method():
        return Foo.averag(Foo.X, Foo.Y)
    @classmethod
    def class_method(cls):
        return cls.averag(cls.X, cls.Y)
foo = Foo()
print(foo.static_method())
print(foo.class_method())

静态方法不受类的影响
类方法：与cls有关
实例方法:与self有关

class Dog():
    @classmethod
    def formal_name(cls):
        return cls.__name__.lower()
    @staticmethod
    def forever_name():
        return "dog"
class Husky(Dog):
    pass
print(Husky.formal_name(),Husky.forever_name())
#husky dog