python之attr

面向对象之attr

class Foo(object):
item = 123

def setattr(self, key, value):
print(key, value)

def getattr(self, item):
print(item)

obj = Foo()
obj.x = 123 #x 123
print(obj.item) #123

※attr的应用

class Local(object):
def init(self):
# 初始化 得到self.storage = {}，每次执行类的__setattr__方法，而不会覆盖之前的键值对
object.setattr(self, "storage", {})

def setattr(self, key, value):
self.storage[key] = value

def getattr(self, key):
return self.storage.get(key)

local = Local() # 实例化local对象，执行__init__方法，执行object.__setattr__的方法:self.storage = {}
local.x1 = 123 # 自动执行__setattr__方法，self.storage = {"x1": 123}
print(local.x1) # 自动执行__getattr__方法，取字典的值，得到 123
local.x2 = 456 # 自动执行__setattr__方法，self.storage = {"x2": 456}
print(local.x2) # 456

自定义简单版local

import threading
"""
storage = {
1111:{'x1':0},
1112:{'x1':1}
1113:{'x1':2}
1114:{'x1':3}
1115:{'x1':4}
}
"""
class Local(object):
def init(self):
object.setattr(self,'storage',{})

def setattr(self, key, value):
ident = threading.get_ident()
if ident in self.storage:
self.storage[ident][key] = value
else:
self.storage[ident] = {key:value}

def getattr(self, item):
ident = threading.get_ident()
if ident not in self.storage:
return
return self.storage[ident].get(item)

local = Local()

def task(arg):
local.x1 = arg
print(local.x1)

for i in range(5):
t = threading.Thread(target=task,args=(i,))
t.start()
执行结果
0
1
2
3
4

加强版local

import threading

"""
storage = {
1111:{'x1':[]},
1112:{'x1':[]}
1113:{'x1':[]}
1114:{'x1':[]}
1115:{'x1':[]},
1116:{'x1':[]}
}
"""

class Local(object):
def init(self):
object.setattr(self, 'storage', {})

def setattr(self, key, value):
ident = threading.get_ident()
if ident in self.storage:
self.storage[ident][key].append(value)
else:
self.storage[ident] = {key: [value, ]}

def getattr(self, item):
ident = threading.get_ident()
if ident not in self.storage:
return
return self.storage[ident][item][-1]

local = Local()

def task(arg):
local.x1 = arg
print(local.x1)

for i in range(5):
t = threading.Thread(target=task, args=(i,))
t.start()