Python：如何保存文件中的对象的列表？ [英] Python: how to save a list with objects in a file?

问题描述

我试图创建不同的对象（使用分类和对象），并将其保存在文件中以编辑或检索它们。

im trying to create diferent objects (using Clases and objects) and saving them in a file to edit or retrive them later. However this how it looks.

GlobalCategories=[]
GlobalContent=[]
def LoadData(x,y):
   import pickle
   with open('bin.dat') as f:
       x,y = pickle.load(f)


def SaveData(x,y):
   import pickle
   with open('bin.dat', 'wb') as f:
      pickle.dump([x,y], f)

def Loader(x,y):
     try:
          LoadData(x,y)
     except:
          SaveData(x,y)

，这段代码片段保存显示如何保存列表的信息（tema是类和其他东西是该类的方法）：

and this the snippet that saves that shows how I save the info the lists (tema is the class and the other stuff are the methods of that class):

newtheme=Tema()
newtheme.setInfo_name(newstr)
newtheme.setInfo_code(newcode)
GlobalCategories.append(newtheme)
SaveData(GlobalContent,GlobalCategories)

X和Y是我存储对象的全局列表（我注意到它保存每个对象的内存中的方向）
当我第一次运行它，它创建文件并将信息保存在文件中，但是如果我关闭它，尝试再次运行它并加载信息，程序擦除信息，并再次创建文件，所以存储的任何东西都消失了。

X and Y are global lists where I store the objects.(i have noticed that it saves the direction in the memory of each object) when i first run it, it creates the file and saves the infomation on the file, however if I close it, try to run it again and load the info, the program erases the information, and creates the file again, so anything that was stored is gone.

我不知道这是否是存储对象的引导方式，或者如果有更好的方式，所以任何建议是非常受欢迎的。

I dont know if this is a propper way to store objects or if there{s a better way so any advice is very welcome.

@abernert：谢谢abarnert！我想做的是保存一个列表里面的两个列表。例如一个列表将保存a make（toyota，nisan等），另一个列表是汽车模型（tundra，murano）。现在每个元素是一个对象，我添加到列表创建时。
newtheme = Theme（）
newtheme.setInfo_name（newstr）
GlobalCategories.append（newtheme）
这是我如何将对象保存在全局列表中。全球类别是这两个列表之一，我想加载后，我已经关闭了程序（它将像例子中的汽车公司的名单）。现在，我有问题是从列表中加载对象，因为我已经关闭并重新启动程序，因为我可以从列表中，当我还没有关闭外壳程序，并编辑他们。
我需要加载和存储的make和车对象在相应的列表，一旦我启动程序，所以我可以操纵他们以后。
再次感谢您的问题！

@abernert: Thank you abarnert! what I want to do is to save a list with two lists inside. for example one list is going to save the a make (toyota, nisan etc) and the other list the car model(tundra, murano). now each element is an object wich i add to a list when created. newtheme=Theme() newtheme.setInfo_name(newstr) GlobalCategories.append(newtheme) this is how i save the object in the global list. GlobalCategories is one of those two list i want to load later after i have closed the program (it would be like the list of car companies from the example). Now, where i have the problem is loading the objects from the lists after i have closed and restarted the program, because i am able to retrive and edit them from the list when i have not closed the shell. I need to load and store the makes and the cars objects in the respective list once i start the program so i can manipulate them later. Thank you abernert once again!

推荐答案

很难知道问题是什么，使用您的 LoadData 和 SaveData 函数。但是，这里是一个小演示，我做你想要的。

It's hard to know what the problem is without context of how you are trying to use your LoadData and SaveData functions. However, here is a little demo that does what I think you want.

import pickle
import random

def load_data():
    try:
        with open("bin.dat") as f:
            x, y = pickle.load(f)
    except:
        x, y = [], []
    return x, y

def save_data(data):
    with open("bin.dat", "wb") as f:
        pickle.dump(data, f)

if __name__ == "__main__":
    x, y = load_data()
    print x, y
    x.append(random.randint(1, 10))
    y.append(random.randint(1, 10))
    save_data([x, y])

从连贯RUNS输出

[] []
[9] [9]
[9, 10] [9, 9]
[9, 10, 2] [9, 9, 4]
[9, 10, 2, 5] [9, 9, 4, 1]
[9, 10, 2, 5, 6] [9, 9, 4, 1, 9]
[9, 10, 2, 5, 6, 10] [9, 9, 4, 1, 9, 1]

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