在Python中创建列表对象类

Question

这是一个基本问题.我正在尝试以下代码:

class SMS_store:

def __init__(self):
    self=[]    #probably something is wrong here

def add_new_arrival(self,from_number,time_arrived,text_of_SMS):
    self.append([False,from_number,time_arrived,text_of_SMS])    #append list to self list
    self[len(self)-1]=tuple(self[len(self)-1])

def message_count(self):
    return len(self)

my_inbox=SMS_store()
my_inbox.add_new_arrival('01234','9:37 AM','How are you?')

但是我收到以下错误:

>>> 
Traceback (most recent call last):
  File "C:\Users\Arnob\Desktop\New Text Document.py", line 15, in <module>
    my_inbox.add_new_arrival('01234','9:37 AM','How are you?')
  File "C:\Users\Arnob\Desktop\New Text Document.py", line 8, in add_new_arrival
    self.append([False,from_number,time_arrived,text_of_SMS])    #append list to self list
AttributeError: 'SMS_store' object has no attribute 'append'
>>>

我的代码有什么问题？

Answer 1

如果要继承自list，请使用以下命令：

class SMS_store(list):
               ^^^^^^

并self从__init__方法中删除该赋值。

也就是说，您可能只想拥有一个包含列表的命名属性：

class SMS_store(object):

   def __init__(self):
      self.messages = []

   def add_new_arrival(self, from_number, time_arrived, text_of_SMS):
      self.messages.append((False,from_number,time_arrived,text_of_SMS))

   def message_count(self):
      return len(self.messages)

my_inbox = SMS_store()
my_inbox.add_new_arrival('01234','9:37 AM','How are you?')

就表示实际消息而言，这听起来像是namedtuple. 它就像一个元组，但允许按名称访问字段。这是一个快速说明：

import collections

SMS = collections.namedtuple('SMS', 'from_number time_arrived text_of_SMS')

sms = SMS(from_number='01234', time_arrived='9:37 AM', text_of_SMS='How are you?')
print sms.text_of_SMS

Answer 2

你可以list像这样子类化

class SMS_store(list):

    def add_new_arrival(self, from_number, time_arrived, text_of_SMS):
        self.append((False, from_number, time_arrived, text_of_SMS))    #append tuple to self

    def message_count(self):
        return len(self)

请注意，__init__除非您想在那里做一些额外的事情，否则没有必要。

你不需要附加一个列表然后把它变成一个元组，你可以直接用()而不是创建元组[]