Python ————反射机制

# commons.py 文件
 
name = "nick"
 
def f1():
    return "This is f1."
 
def f2():
    return "This is f2."
 
def nb():
    return "This is niubily."
 
 
 
# index.py 文件
import commons
 
#根据字符串的形式去某个模块中寻找东西
target_func = getattr(commons,"f1")     # 找函数
result = target_func()
print(result)
 
target_func = getattr(commons,"name")   # 找全局变量
print(target_func)
 
target_func = getattr(commons,"age",None)   # 找不到返回None
print(target_func)
 
#根据字符串的形式去某个模块中判断东西是否存在
tarhas_func = hasattr(commons,"f5")     # 找函数
print("before:",tarhas_func)
 
# tarhas_func = hasattr(commons,"name") # 找全局变量
# print(tarhas_func)
 
#根据字符串的形式去某个模块中设置东西
setattr(commons,"f5","lambda x: return \"This is new func.\"")  # 设置一个函数
setattr(commons,"age",18)       # 设置全局变量
 
tarhas_func = hasattr(commons,"f5")     # 检查函数是否存在
print("after:",tarhas_func)
 
#根据字符串的形式去某个模块中删除东西
delattr(commons,"f5")       # 删除一个函数
 
tarhas_func = hasattr(commons,"f5")     # 检查函数是否存在
print("end:",tarhas_func)

class Foo:
   def __init__(self,name,age):
       self.name=name
       self.age=age

   def show(self):
        print("获取到了该函数方法")

obj=Foo(‘2018世界杯‘,2018)
 #hasattr 是否存在字段
print(hasattr(obj,‘name‘))
#getattr获取信息
getname=getattr(obj,‘name‘)
print(getname)
#setattr赋值
setattr(obj,‘time‘,‘2018-6-16‘)
print(obj.time)
#delattr删除
delattr(obj,‘name‘)
print(obj.name)#删除后报错AttributeError: ‘Foo‘ object has no attribute ‘name‘