Python的issubclass()是一个内置函数，用于检查传递的类是否是指定的另一个类的子类。

Python issubclass()的语法如下：

issubclass(class，classinfo)

如果class是classinfo的子类(直接，间接或者虚拟)，则函数返回True。

classinfo可以是一个类，也可以是一个类对象的元组，如果它是一个类对象的元组，则将对元组中的每个条目检查class(第一个参数)。

Python issubclass()示例

1.很明显，在Python中使用继承时，将使用issubclass()函数。这是一个层次结构，其中Employee类从Person继承，而Manager类从Employee继承，因此这里有多级继承方案。让我们使用issubclass()检查不同的组合。

class Person:
    def __init__(self, name, age):
        self.name = name
        self.age = age

    def display_info(self):
        print('Name:', self.name)
        print('Age:', self.age)

class Employee(Person):
    def __init__(self, emp_id, department, name, age):
        super().__init__(name, age)
        self.emp_id = emp_id
        self.department = department

    def display_info(self):
        super().display_info()
        print('Id:', self.emp_id)
        print('Department:', self.department)

class Manager(Employee):
    def __init__(self, perks, emp_id, department, name, age):
        super().__init__(emp_id, department, name, age)
        self.perks = perks

    def display_info(self):
        super().display_info()
        print('Perks:', self.perks)

print("issubclass(Employee, Person):", issubclass(Employee, Person))
print("issubclass(Manager, Person):", issubclass(Manager, Person))
print("issubclass(Manager, Employee):", issubclass(Manager, Employee))
print("issubclass(Employee, Manager):", issubclass(Employee, Manager))
print("issubclass(Person, Employee):", issubclass(Person, Employee))

输出：

issubclass(Employee, Person): True
issubclass(Manager, Person): True
issubclass(Manager, Employee): True
issubclass(Employee, Manager): False
issubclass(Person, Employee): False

Manager也间接地从Person继承而来，所以它也是Person类型的，因此issubclass(Manager，Person)返回true。反之，虽然Manager不是Employee的子类，也不是True，Person也不是Employee的子类，所以这两个函数调用都返回false。

2.在此示例中，我们将在issubclass()函数中将元组作为第二个参数传递。

class Person:
    def __init__(self, name, age):
        self.name = name
        self.age = age

    def display_info(self):
        print('Name:', self.name)
        print('Age:', self.age)

class Employee(Person):
    def __init__(self, emp_id, department, name, age):
        super().__init__(name, age)
        self.emp_id = emp_id
        self.department = department

    def display_info(self):
        super().display_info()
        print('Id:', self.emp_id)
        print('Department:', self.department)

class Manager(Employee):
    def __init__(self, perks, emp_id, department, name, age):
        super().__init__(emp_id, department, name, age)
        self.perks = perks

    def display_info(self):
        super().display_info()
        print('Perks:', self.perks)

print("issubclass(Employee, (str, list))):", issubclass(Employee, (str, list)))
print("issubclass(Employee, (str, list, Person)):", issubclass(Employee, (str, list, Person)))
print("issubclass(Manager, (str, list)):", issubclass(Manager, Employee))
print("issubclass(Person, (Employee, Manager)):", issubclass(Person, (Employee, Manager)))
print("issubclass(Person, (Employee, Manager, object)):", issubclass(Person, (Employee, Manager, object)))

输出：

issubclass(Employee, (str, list))): False
issubclass(Employee, (str, list, Person)): True
issubclass(Manager, (str, list)): True
issubclass(Person, (Employee, Manager)): False
issubclass(Person, (Employee, Manager, object)): True

由于Employee不是str或者list的子类，因此第一次调用显然返回false。
第二个是正确的，因为Employee是Person的子类，并且元组中的一项通过了检查。
最后一次调用issubclass(Person，(Employee，Manager，object))返回true，因为object是Python中所有类的超类。