如何在泡菜文件 python 中加载一些变量？ 如使用 scipy 或 hdf5storage 加载 matlab 文件

Question

Let's say I have saved a pickle file with multiple variables:

import pickle

with open("file.pickle", "wb") as f:
    pickle.dump((a,b,c,d,e,f), f)

The file can be loaded with:

with open("file.pickle", "rb") as f:
    a,b,c,d,e,f= pickle.load(f) 

Is there a way to read just the first four variables other than saving the four variables in a separate file?

with open("file.pickle", "rb") as f:
    a,b,c,d=  ?? #load the first four variables only

Answer 1

You didn't save 6 variables to a pickle file. That's not how pickles or variables work.

You constructed a 6-element tuple and wrote a pickle-format serialization of that tuple to a file. The pickle format does not support deserializing only parts of a serialized object; you have to load the whole tuple.

The pickle format is a sequence of instructions for building objects, and just like following half the recipe to bake a cake won't bake half a cake, you can't load half a pickle and get half the tuple you serialized.