def hasattr(*args, **kwargs): # real signature unknown"""Return whether the object has an attribute with the given name.This is done by calling getattr(obj, name) and catching AttributeError."""pass

getattr()源码解释

class A:name = 'he'age = 23
print(A.name)    #he
print(A.age)       #23#使用反射的形式,操作类的属性
print(getattr(A, 'name'))
>>>
he

#使用反射操作类中的方法
class A:number = 1def func(self):print('in the func')
a = A()
ret = getattr(a,'func')      #得到了func方法的内存地址
ret()                              #调用func（）方法

def hasattr(*args, **kwargs): # real signature unknown"""Return whether the object has an attribute with the given name.This is done by calling getattr(obj, name) and catching AttributeError."""pass

hasattr的源码解释

#例子1：通过hasattr判断，再用getattr来取值。
class A:name = 'he'age = 23inp = input('>>>:')
if hasattr(A,inp):print(getattr(A,inp))
else:print('A类中没有对应的属性')>>>:name
he
>>>:sex
A类中没有对应的属性#例子2
class Student:def __init__(self,name,age):self.name = nameself.age = agedef show(self):for key in self.__dict__:                 #__dict__查看对象的所有属性print(key,self.__dict__[key])         # key self.__dict__[key]s = Student('he',23)
# s.show()if hasattr(s,'show'):func = getattr(s,'show')        #返回方法的内存地址,赋值给func()func()
>>>
name he
age 23

def setattr(x, y, v): # real signature unknown; restored from __doc__"""Sets the named attribute on the given object to the specified value.setattr(x, 'y', v) is equivalent to ``x.y = v''"""pass

setattr的源码解释

#正常情况下，想给对象设置一个值。
class Student:def __init__(self,name,age):self.name = nameself.age = agedef show(self):for key in self.__dict__:      #__dict__查看对象的所有属性print(key,self.__dict__[key]) # key self.__dict__[key]s = Student('he',23)
s.sex = 'male'
print(s.sex)
>>>
male#除了上面的方式之外，还有一种方式为对象设置属性，通过反射的形式.
setattr(s,'sex','male')
print(s.__dict__)
print(s.sex)
>>>
{'name': 'he', 'age': 23, 'sex': 'male'}

#创建一个函数，通过setattr给对象绑上这个函数
class Student:def __init__(self,name,age):self.name = nameself.age = agedef show(self):for key in self.__dict__:         #__dict__查看对象的所有属性print(key,self.__dict__[key]) # key self.__dict__[key]s = Student('he',23)
def func1(a,b):print(a,b)
setattr(s,'func',func1)       #把普通函数当做函数添加到对象空间中
s.func(1,2)
print(s.__dict__)
>>>:
1 2
{'name': 'he', 'age': 23, 'func': <function func1 at 0x000001F16D252F28>}

class Student:def __init__(self,name,age):self.name = nameself.age = agedef show(self):for key in self.__dict__:      #__dict__查看对象的所有属性print(key,self.__dict__[key]) # key self.__dict__[key]s = Student('he',23)
#正常方法
del s.age
print(s.__dict__)#通过delattr反射的方式
delattr(s,'age')
print(s.__dict__)

import sys
print(getattr(sys, 'path'))
>>>
C:\Python36\python.exe E:/python_training_s1/day21/day21_training.py
['E:\\python_training_s1\\day21', 'E:\\python_training_s1', 'C:\\Python36\\python36.zip', 'C:\\Python36\\DLLs', 'C:\\Python36\\lib', 'C:\\Python36', 'C:\\Users\\hesihao\\AppData\\Roaming\\Python\\Python36\\site-packages', 'C:\\Python36\\lib\\site-packages', 'D:\\pycharm\\PyCharm 2018.1.4\\helpers\\pycharm_matplotlib_backend']

# 方式一：sys.modules[__main__]
import sys
name = 'he'
def foo():print('这是本模块的函数foo')print(getattr(sys.modules['__main__'], 'name'))
getattr(sys.modules['__main__'], 'foo')()
>>>
he
这是本模块的函数foo

#通过sys.modules[__name__]反射当前模块import sys
name = 'he'
def foo():print('这是本模块的函数foo')
getattr(sys.modules[__name__],'foo')()
>>>
这是本模块的函数foo

import sys
class Student:def __init__(self,name,age):self.name = nameself.age = agedef show(self):for key in self.__dict__:      #__dict__查看对象的所有属性print(key,self.__dict__[key]) # key self.__dict__[key]main = sys.modules[__name__]
cls = getattr(main,'Student')
he = cls('小何',23)