Question

我希望能够将多个对象添加到pickle文件中，以后能够检索它。我到了可以保存对象的地步，但是当我加载文件时，只加载了最后一个条目。我的错是什么？

import pickle

class People():
    def __init__(self, name, surname, age, mobile_no, home_no):
        self.name = name
        self.surname = surname
        self.age = age
        self.mobile_no = mobile_no
        self.home_no = home_no

    def DisplayContacts(self):
        print("First Name: \t", self.name)
        print("Surname: \t", self.surname)
        print("Age: \t", self.age)
        print("Mobile Number: \t", self.mobile_no)
        print("Home Number: \t", self.home_no)
        print()


def addContact():
    newname = str(input("First name: \t"))
    newsurname = str(input("Surname: \t"))
    newage = int(input("Age: \t"))
    newmobile_no = int(input("Mobile Number: \t"))
    newhome_no = int(input("Home Number: \t"))
    newContact = People(newname, newsurname, newage, newmobile_no, newhome_no) 
    return newContact

cont = 1

contacts = []


while cont == 1:
    user = input("Do you want to add contact? (Y/N)")
    if user == "Y" or user == "y":
        print ("works")
        contacts.append(addContact())
        file = open("List.pickle", "wb")
        pickle.dump(contacts, file, pickle.HIGHEST_PROTOCOL)
        file.close()
    else:
        print ("111")
        cont = 0

useropen = input("open file? (Y/N)")
if useropen == "Y" or useropen == "y":
    with open ("List.pickle", "rb") as pickled_file:
        contacts = pickle.load(pickled_file)
else:
    print("Null")

现在，当我尝试加载文件时，它似乎是空的：

import pickle

class People():
    def __init__(self, name, surname, age, mobile_no, home_no):
        self.name = name
        self.surname = surname
        self.age = age
        self.mobile_no = mobile_no
        self.home_no = home_no

    def DisplayContacts(self):
        print("First Name: \t", self.name)
        print("Surname: \t", self.surname)
        print("Age: \t", self.age)
        print("Mobile Number: \t", self.mobile_no)
        print("Home Number: \t", self.home_no)
        print()


def addContact():
    newname = str(input("First name: \t"))
    newsurname = str(input("Surname: \t"))
    newage = int(input("Age: \t"))
    newmobile_no = int(input("Mobile Number: \t"))
    newhome_no = int(input("Home Number: \t"))
    newContact = People(newname, newsurname, newage, newmobile_no, newhome_no) 
    return newContact

cont = 1

contacts = []


while cont == 1:
    user = input("Do you want to add contact? (Y/N)")
    if user == "Y" or user == "y":
        print ("works")
        contacts.append(addContact())
        file = open("CList.pickle", "ab")
        pickle.dump(contacts, file, pickle.HIGHEST_PROTOCOL)
        file.close()
    else:
        print ("111")
        cont = 0

useropen = input("open file? (Y/N)")
if useropen == "Y" or useropen == "y":

    with open ("CList.pickle", "rb") as pickled_file:
        contacts = pickle.load(pickled_file)
else:
    print("Null")

Answer 1

您正在while循环的每次迭代中截断您的Pickle文件，因为您是以"wb"模式打开它。

由于您在循环期间不断向contacts列表添加联系人（然后在每次迭代时将一个单独的副本转储到另一个联系人 - 可能不是您想要的那个），我只需要整个pickle转储部分代码并在while循环之后移动它，转储完整的联系人列表一次 - 不需要多个对象。

Answer 2

您正在使用模式wb打开您的pickle文件，该文件会截断（在写入任何新内容之前将文件设置为空）。您想要的模式是a，可以打开以进行追加。

Answer 3

添加到@Ethan Furman所说的内容，Windows和unix（reference）中'b'的功能似乎有所不同。您的代码可能在unix上运行良好，但会在windows os上截断

pickle文件中的多个对象

3 个答案: