Python isinstance()

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

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

# Output: True

isinstance() 语法

isinstance() 的语法是

isinstance(object, classinfo)

isinstance() 参数

isinstance() 接受两个参数

• object - 要检查的 对象
• classinfo - 类、类型或 元组 形式的类和类型

isinstance 返回值

isinstance() 返回

• 如果 对象 是类或元组中任何元素的实例或子类，则返回 True
• 否则返回 False

如果 classinfo 不是类型或类型元组，则会引发 TypeError 异常。

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)))

输出

True
False
True

示例 2：isinstance() 与原生类型的使用

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

另请阅读

• Python type()
• 用于区分 type() 和 isinstance() 的 Python 程序