python中的反射功能是由以下四个内置函数提供：hasattr、getattr、setattr、delattr，改四个函数分别用于对对象内部执行：检查是否含有某成员、获取成员、设置成员、删除成员。
获取成员: getattr
class Foo:
def __init__(self, name, age):
self.name = name
self.age = age
obj = Foo('klvchen', 18)
inp = input('>>>')
v = getattr(obj, inp)
print(v)
运行结果:
>>>name klvchenclass Foo: def __init__(self, name, age): self.name = name self.age = age def show(self): return "%s-%s" %(self.name, self.age) obj = Foo('klvchen', 18) func = getattr(obj, 'show') print(func) res = func() print(res)
运行结果:
<bound method Foo.show of <__main__.Foo object at 0x00000234F6942588>> klvchen-18
检查是否含有成员: hasattr
class Foo:
def __init__(self, name, age):
self.name = name
self.age = age
def show(self):
return "%s-%s" %(self.name, self.age)
obj = Foo('klvchen', 18)
print(hasattr(obj, 'name1'))
运行结果:
False
设置成员: setattr
class Foo:
def __init__(self, name, age):
self.name = name
self.age = age
def show(self):
return "%s-%s" %(self.name, self.age)
obj = Foo('klvchen', 18)
# print(hasattr(obj, 'name1'))
setattr(obj, 'key', 'value')
print(obj.key)
运行结果:
value
删除成员: delattr
class Foo:
def __init__(self, name, age):
self.name = name
self.age = age
def show(self):
return "%s-%s" %(self.name, self.age)
obj = Foo('klvchen', 18)
print(obj.name)
delattr(obj, 'name')
print(obj.name)
运行结果:
klvchen AttributeError: 'Foo' object has no attribute 'name'
通过字符串的形式操作对象中的成员
class Foo: stat = '666' def __init__(self, name, age): self.name = name self.age = age res = getattr(Foo, 'stat') print(res)
运行结果:
666
创建两个文件，s1.py 和 s2.py
s2.py 内容如下:
NAME = 'klvchen' def func(): return 'func'
s1.py 内容如下:
import s2 res1 = getattr(s2, 'NAME') print(res1) res2 = getattr(s2, 'func') result = res2() print(result)
运行 s1.py 文件:
klvchen func
创建两个文件，s1.py 和 s2.py
s2.py 内容如下:
NAME = 'klvchen' def func(): return 'cwe' class Foo: def __init__(self): self.name = 666
s1.py 内容如下:
import s2 res1 = getattr(s2, 'NAME') print(res1) res2 = getattr(s2, 'func') result = res2() print(result) cls = getattr(s2, 'Foo') print(cls) obj = cls() print(obj) print(obj.name)
运行 s1.py 文件，运行结果：
klvchen cwe <class 's2.Foo'> <s2.Foo object at 0x000001CFCDBB2438> 666
创建两个文件，s1.py 和 s2.py
s2.py 内容如下:
def f1(): return '首页' def f2(): return '新闻' def f3(): return '精华'
s1.py 内容如下:
import s2
inp = input('请输入要查看的URL: ')
if hasattr(s2, inp):
func = getattr(s2, inp)
result = func()
print(result)
else:
print('404')
运行 s1.py 文件，运行结果：
请输入要查看的URL: f1 首页
