Python笔记属性值设置和判断变量是否存在

　　介绍Python设置属性值方法setattr()和判断变量是否存在的方法 以属性名为变量的方式给一个对象添加属性
　　使用 setattr 方法 obj = SomeClass() key = ＂key_name＂ val = ＂key_value＂ setattr(obj, key, val) print(obj.key_name)
　　示例：给报文字段赋值 from scapy.all import * layer = {＂ether＂:＂dst=＂33:33:00:01:00:02＂,src=＂00:0c:29:d9:98:c7＂＂} Ethernet_field = layer.setdefault(＂ether＂) ethernet = Ether(type=0x86dd) fields = dict(((lambda a:(a[0].strip(＂＂＂),a[1].strip(＂＂＂))) (field.split(＂=＂)) for field in Ethernet_field.split(＂,＂))) for key, val in fields.items():     setattr(ethernet, key, val)  ethernet.show()
　　out: >>> ethernet.show() ###[ Ethernet ]###   dst       = 33:33:00:01:00:02   src       = 00:0c:29:d9:98:c7   type      = IPv6 判断变量是否存在
　　三种方法： locals().keys() dir() vars() ethernet = ＂Ether＂ dhcpv6 = ＂dhcpv6_solicit＂ message = [＂ethernet＂,＂ip＂,＂udp＂,＂dhcpv6＂] del_message = [] for layer_i, value in enumerate(message):                  if message[layer_i] not in locals().keys():         del_message.append(value) for m in del_message:     message.remove(m) print(f＂message:{message}＂)
　　运行结果： C:UsersDELL>python3 test_locals.py message:[＂ethernet＂, ＂dhcpv6＂]
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