Python isinstance（）

Python isinstance() function is used to check if an object is an instance of the specified class or not.

Python的isinstance（）函数用于检查对象是否为指定类的实例。

Python isinstance（） (Python isinstance())

Python isinstance() function syntax is:

Python的isinstance（）函数语法为：

isinstance(object, classinfo)

This function returns True if the object is instance of classinfo argument or instance of classinfo subclass.

如果对象是classinfo参数的实例或classinfo子类的实例，则此函数返回True 。

If the object is not an instance of classinfo or its subclass, then the function returns False.

如果对象不是classinfo或其子类的实例，则该函数返回False 。

classinfo argument can be a tuple of types. In that case, isinstance() will return True if the object is an instance of any of the types.

classinfo参数可以是类型的元组 。 在这种情况下，如果对象是任何类型的实例，则isinstance（）将返回True。

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

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

Python isinstance（）示例 (Python isinstance() example)

Let’s look at some simple examples of isinstance() function with built-in data types, such as string, tuple, list, dict, bytes etc.

让我们看一下具有内置数据类型的isinstance（）函数的一些简单示例，例如字符串 ，元组， 列表 ， 字典 ， 字节等。

Python isinstance（）编号 (Python isinstance() number)

i = 10
print('i is int:', isinstance(i, int))

f = 10.5
print('f is float:', isinstance(f, float))

Output:

输出：

i is int: True
f is float: True

Python isinstance（）字符串 (Python isinstance() string)

s = 'a'
print('s is str:', isinstance(s, str))

Output:

输出：

s is str: True

Python isinstance（）字节 (Python isinstance() bytes)

b = bytes('abc', 'utf-8')
print('b is bytes:', isinstance(b, bytes))

Output:

输出：

b is bytes: True

Python isinstance（）元组 (Python isinstance() tuple)

t = (1, 2)
print('t is tuple:', isinstance(t, tuple))

Output:

输出：

t is tuple: True

Python isinstance（）列表 (Python isinstance() list)

li = []
print('li is list:', isinstance(li, list))

Output:

输出：

li is list: True

Python isinstance（）字典 (Python isinstance() dict)

d = {}
print('d is dict:', isinstance(d, dict))

Output:

输出：

d is dict: True

Python isinstance（）类和继承 (Python isinstance() class and inheritance)

Let’s look at an example of isinstance() function with custom class and inheritance with multiple classes.

我们来看一个带有自定义类和多个类继承的isinstance（）函数的示例。

class Person:
    name = ''


class Employee(Person):
    id = 0


p = Person()
e = Employee()

print('p isinstance of Person:', isinstance(p, Person))
print('p isinstance of Employee:', isinstance(p, Employee))

print('e isinstance of Person:', isinstance(e, Person))
print('e isinstance of Employee:', isinstance(e, Employee))

Output:

输出：

p isinstance of Person: True
p isinstance of Employee: False
e isinstance of Person: True
e isinstance of Employee: True

Python isinstance（）类的元组 (Python isinstance() tuple of classes)

print('p is an instance of Person or Employee:', isinstance(p, (Person, Employee)))
print('e is an instance of Person or Employee:', isinstance(e, (Person, Employee)))

Output:

输出：

p is an instance of Person or Employee: True
e is an instance of Person or Employee: True

摘要 (Summary)

Python isinstance() is a utility function to check if an object is of a specific type or not. We can use it to perform a type check and perform operations based on the type of object.

Python isinstance（）是一种实用程序函数，用于检查对象是否为特定类型。 我们可以使用它来执行类型检查并根据对象的类型执行操作。

Reference: Official Documentation

参考： 官方文档

翻译自: https://www.journaldev.com/22932/python-isinstance