python 反射

1、getattr
class F:
    def __init__(self, name):
        self.name = name

    def show(self):
        return self.name
obj = F('tom')
s = getattr(obj, 'name')
r = getattr(obj, 'show')
print(s)  # tom
print(r())# tom

getattr反射类F中的属性，getattr(对象，类属性)

2、hasattr

class F:
    def __init__(self, name):
        self.name = name

    def show(self):
        return self.name
obj = F('tom')
s = hasattr(obj, 'name')
h = hasattr(obj, 'age')
print(s) # Ture
print(h) # False

hasattr判断类中存在的属性，如果存在返回Ture,如果不存在返回False

3、setattr

class F:
    def __init__(self, name):
        self.name = name

obj = F('tom')
print(obj.name)  # tom
# 对已存在的属性值赋值
setattr(obj, 'name', 'jack')
print(obj.name)  # jack
# 设置新的属性值
setattr(obj, 'age', 12)
print(obj.age)   # 12

setattr 用于设置属性值，该属性不一定是存在的

4、delattr

class F:

    def __init__(self, name):
        self.name = name

obj = F('tom') 
print(obj.name)  # tom
delattr(obj, 'name')
obj.name
当执行delattr 后，在调用name属性，会提示“AttributeError: 'F' object has no attribute 'name'”

delattr 用于删除属性值