python - 如何在Python中反转str(class)？

Question

我需要根据相同类型类的非正式字符串表示来定义类的新实例。在 Python 中执行此操作的干净方法是什么？

程序1.py:

fileHandle = open("filename.txt", "wb")
instance = className()
instance.a = 2
instance.b = 3.456
fileHandle.write(str(instance))

filename.txt(运行program1.py后):

<className a=2, b=3.456>

程序2.py:

instance = className()
with open("filename.txt", "r") as fileHandle:
    for fileLine in fileHandle:
        ##### How do I grab the contents of the file line and get them in variables? #####
        (instance.a, instance.b) = magicFunction(fileLine)
        # I seem to have forgotten the contents of magicFunction(). Can someone remind me?

Answer 1

一般来说，python str 函数旨在以人类可读的方式打印内容，而不是您想要使用的计算机可读方式。如果您控制 program1.py，则 pickle 模块可以满足您的需求。

Program1.py:
    import pickle
    [rest of code unrelated to printing]
    pickle.dump(instance,fileHandle)
Program2.py:
    instance = pickle.load(fileHandle)