如何腌制和解封答案

【问题标题】：How to pickle and unpickle如何腌制和解封
【发布时间】：2015-10-14 14:18:24
【问题描述】：

import  pickle
variety = ["sweet", "box", "cat"]
shape = ["back","spear", "log"]
pickleFile = open("pickle.txt", 'w')
pickle.dump(variety, pickleFile)
pickle.dump(shape, pickleFile)
pickleFile.close()

pickleFile = open("pickle.txt", 'r')
test = pickle.load(pickleFile)
shape = pickle.load(pickleFile)

print ("variety : ", test, " shape : ", shape)
pickleFile.close()

当我运行上面的代码时，我得到以下错误

line 6, in <module>
pickle.dump(variety, pickleFile)
TypeError: must be str, not bytes

而且我不确定是否可以在变量“测试”中解酸或者不是因为我已经用变量'variety'腌制了

【问题讨论】：

标签： python python-3.x pickle

【解决方案1】：

根据help(pickle.dump)，

file 参数必须有一个 write() 方法，该方法接受单个字节参数。因此它可以是为二进制打开的文件对象写入、io.BytesIO 实例或任何其他满足这个界面。

看来您必须以二进制模式打开文件。不要忘记对loading 也这样做。

import  pickle
variety = ["sweet", "box", "cat"]
shape = ["back","spear", "log"]
pickleFile = open("pickle.txt", 'wb')
pickle.dump(variety, pickleFile)
pickle.dump(shape, pickleFile)
pickleFile.close()

pickleFile = open("pickle.txt", 'rb')
test = pickle.load(pickleFile)
shape = pickle.load(pickleFile)

print ("variety : ", test, " shape : ", shape)
pickleFile.close()

结果：

variety :  ['sweet', 'box', 'cat']  shape :  ['back', 'spear', 'log']

【讨论】：

【解决方案2】：

您的问题是您正在尝试将腌制对象写入文本文件。这就像试图用 MS Word 编写数据库一样。

腌制文件的正确文件扩展名是“.pkl”。该文件还必须以二进制模式写入和读取。

我的建议是将文件扩展名更改为“.pkl”，然后使用两个with 循环来整理您的代码。加载和写入的更正就像将'w'更改为'wb'一样简单，结果如下所示：

import  pickle
variety = ["sweet", "box", "cat"]
shape = ["back","spear", "log"]
with open("pickle.pkl", 'wb') as pickleFile:
    pickle.dump(variety, pickleFile)
    pickle.dump(shape, pickleFile)
    pickleFile.close()

with open("pickle.pkl", 'rb') as pickleFile:
    test = pickle.load(pickleFile)
    shape = pickle.load(pickleFile)

print ("variety : ", test, " shape : ", shape)
pickleFile.close()

【讨论】：