Python isinstance()用法及代碼示例

numbers = [1, 2, 3, 4, 2, 5]

# check if numbers is instance of list
result = isinstance(numbers, list)
print(result)

# Output: True

isinstance() 語法

用法:

isinstance(object, classinfo)

參數：

isinstance() 有兩個參數：

• object-object被檢查
• classinfo- 類、類型或類和類型的元組

isinstance 返回值

isinstance() 返回：

• True 如果 object 是類的實例或子類或元組的任何元素
• False 否則

如果 classinfo 不是類型或類型的元組，則會引發 TypeError 異常。

示例 1：isinstance() 如何工作？

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

示例 2：isinstance() 與本機類型一起工作

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