Python isinstance()

如果函数的第一个参数是第二个参数的实例或子类，则isinstance()函数返回 true。实际上，我们可以说这个函数用于检查给定的对象是给定类的实例还是子类。

 **isinstance(object, classinfo) ** # Where object specify name of the object

isinstance()参数:

接受 2 个参数，其中第一个参数是 string、int、float、long 或自定义类型的对象。

isinstance()返回值

它返回真或假的布尔值。

| 投入 | 返回值 |
| 对象是一个实例 | 真实的 |
| 对象不是实例 | 错误的 |
| classinfo 不是类型或类型元组 | TypeError exception |

Python 中isinstance()方法的示例

示例isinstance()是如何工作的？

 class Foo:
  a = 5

fooInstance = Foo()

print(isinstance(fooInstance, Foo))
print(isinstance(fooInstance, (list, tuple)))
print(isinstance(fooInstance, (list, tuple, Foo))) 

输出:

True
False
True 

示例 2:使用本机类型处理isinstance()

 numbers = [1, 2, 3]

result = isinstance(numbers, list)
print(numbers,'instance of list?', result)

result = isinstance(numbers, dict)
print(numbers,'instance of dict?', result)

result = isinstance(numbers, (dict, list))
print(numbers,'instance of dict or list?', result)

number = 5

result = isinstance(number, list)
print(number,'instance of list?', result)

result = isinstance(number, int)
print(number,'instance of int?', result) 

输出:

[1, 2, 3] instance of list? True
[1, 2, 3] instance of dict? False
[1, 2, 3] instance of dict or list? True
5 instance of list? False
5 instance of int? True 

示例isinstance()的工作方式另一个示例？

 # Python `isinstance()` function example  
class Student:  
    id = 101  
    name = "John"  
    def __init__(self, id, name):  
        self.id=id  
        self.name=name  

student = Student(1010,"John")  
lst = [12,34,5,6,767]  
# Calling function   
print(isinstance(student, Student)) # isinstance of Student class  
print(isinstance(lst, Student)) 

输出:

True
False