创建一个类来生成ID

Question

我已经读了一些关于自动化对象id的创建，但仍然迷路了......我试图将以下代码以Algorias here ......

我想要实现的是一个类，它是所有新的id请求的资源。其中的逻辑是，如果是在同一个地方，应该更容易管理...

但是当我到X设置为订单的一个实例，我得到如下：

>>> x = Order() 

Traceback (most recent call last): 
    File "<pyshell#20>", line 1, in <module> 
    x = Order() 
    File "C:\Python27\delete.py", line 17, in __init__ 
    self.uid = Id_Class.new_id("Order") 
TypeError: unbound method new_id() must be called with Id_Class instance as first argument (got str instance instead) 

任何帮助将不胜感激

import itertools 

class Id_Class(object):  
    new_id = itertools.count(1000).next 
    order_id = itertools.count(1000).next 
    person_id= itertools.count(1000).next 
    def new_id(self, t): # t = type of id required 
     if t == "Order": 
      self.id = Id_Class.order_id() 
     elif t == "Person": 
      self.id = Id_Class.person_id() 

class Order(object): 
    def __init__(self): 
     self.uid = Id_Class.new_id("Order") 
     self.cus='Test' 

class Person(object): 
    pass 

Answer 1

您需要在函数声明上使用@staticmethod装饰器。

class Id_Class(object):  
    new_id = itertools.count(1000).next 
    order_id = itertools.count(1000).next 
    person_id= itertools.count(1000).next 

    @staticmethod 
    def new_id(t): # t = type of id required 
     if t == "Order": 
      return Id_Class.order_id() 
     elif t == "Person": 
      return Id_Class.person_id() 

Answer 2

这可能是一个类的方法。类方法接收类作为第一个参数（不像常规方法那样是类的实例）。这样做，您还需要返回值，以便调用者可以访问ie。

class Id_Class(object):  
    new_id = itertools.count(1000).next 
    order_id = itertools.count(1000).next 
    person_id= itertools.count(1000).next 

    @classmethod 
    def new_id(cls, t): # t = type of id required 
     if t == "Order": 
      return cls.order_id() 
     elif t == "Person": 
      return cls.person_id() 
     else: 
      raise ValueError("Must be 'Order' or 'Person'") 

尽管你真的不需要一个类在这里都：

new_id = itertools.count(1000).next 
order_id = itertools.count(1000).next 
person_id= itertools.count(1000).next 
def new_id(t): # t = type of id required 
    if t == "Order": 
     return order_id() 
    elif t == "Person": 
     return person_id() 

然后可以通过简单地称为：

my_order_id=new_id('Order') 
my_person_id=new_id('Person') 

Answer 3

因为你调用NEW_ID像静态方法，请尝试添加@staticmethod来代替：

class Id_Class(object):  
    new_id = itertools.count(1000).next 
    order_id = itertools.count(1000).next 
    person_id= itertools.count(1000).next 

    @classmethod 
    def new_id(cls, t): # t = type of id required 
     if t == "Order": 
      return Id_Class.order_id() 
     elif t == "Person": 
      return Id_Class.person_id()