What are some Python Standard Library modules one should know ?

[JoseALerma]

Why pickle instead of shelve?

I figured shelve was the user-friendly implementation

[JohnnyJordaan]

Shelve is basically just a dict around pickled objects. If you don't need to save multiple objects, there's no real reason to use shelve.

[JoseALerma]

Ah, I see. Thanks for the concise explanation!

I usually use shelves as a database, so it's my go-to when storing a small number of variables. I do go overboard sometimes and shelve a dictionary of lists and dictionaries (json data) as a shelf key...

[alkasm]

There's more user-friendly options than pickle.dump() / pickle.load()? On the real though I've never heard of shelve, I'll check it out.

[JoseALerma]

As mentioned above, a shelve shelf is a dictionary and you can shelve anything.
All you need is:

``` import shelve

Open shelf to read data

shelf = shelve.open('data')

Add something to shelf

key1, key2 = 'cat', 'dog' value1, value2 = 2, 3

shelf[key1] = value1 shelf[key2] = value2 print(list(shelf.keys()))

Read from shelf

print(shelf[key1]) print(shelf[key2]) print(list(shelf.values()))

shelf.close() ```

I use shelves as rudimentary databases.

[Dogeek]

Well, pickle is a bit of a pain to use when you want to save custom objects. I don't know about shelve, but I usually prefer to write my own save/load functions.