Python isinstance（）

缺乏、安全感 2022-01-12 13:47 226阅读 0赞

The isinstance() function checks if the object (first argument) is an instance or subclass of classinfo class (second argument).

The syntax of isinstance() is:

isinstance(object, classinfo)

## isinstance() Parameters ##

The isinstance() takes two parameters:

*  **object** - `object` to be checked
 *  **classinfo** - class, type, or tuple of classes and types

--------------------

## Return Value from isinstance() ##

The isinstance() returns:

*  `True` if the object is an instance or subclass of a class, or any element of the tuple
 *  `False` otherwise

If classinfo is not a type or tuple of types, a `TypeError` exception is raised.

--------------------

## Example 1: How isinstance() works? ##

class Foo:
      a = 5
      
    fooInstance = Foo()
    
    print(isinstance(fooInstance, Foo))
    print(isinstance(fooInstance, (list, tuple)))
    print(isinstance(fooInstance, (list, tuple, Foo)))
    
    
    When you run the program, the output will be:

True
    False
    True

## Example 2: Working of isinstance() with Native Types ##

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)
    
    
    When you run the program, the output will be:

[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

转载于:https://www.cnblogs.com/Xingtxx/p/11046070.html