Python isinstance()

如果函數的第一個參數是第二個參數的實例或子類，則isinstance()函數返回 true。實際上，我們可以說這個函數用於檢查給定的對象是給定類的實例還是子類。

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

接受 2 個參數，其中第一個參數是 string、int、float、long 或自定義類型的對象。

它返回真或假的布爾值。

| 投入 | 返回值 |
| 對象是一個實例 | 真實的 |
| 對象不是實例 | 錯誤的 |
| classinfo 不是類型或類型元組 | TypeError exception |

 class Foo:
  a = 5

fooInstance = Foo()

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

輸出:

True
False
True 

 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) 

輸出:

[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 

 # 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)) 

輸出:

True
False