Python Forum

Pickle is a great way to save and load files because it encode the data before storing it. Especially numbers. Before we use pickle we need a way to grab the current_directory the file we are working in is inside. For this we use pathlib.Path -

from pathlib import Path
current_directory = Path(__file__).parent

Excellent. For this tutorial I will be using a txt file. In order to get through directories I am going to use os -

from pathlib import Path
import os
current_directory = Path(__file__).parent
file = os.path.join(current_directory, 'DataFolder', 'Data.txt') #os.path.join joins together all the strings to return a path

Now it is time to use pickle. The two modules we are using from pickle are pickle.dump (save) and pickle.load (load). Here is pickle.save in actions -

from pathlib import Path
import os, pickle
current_directory = Path(__file__).parent #Get current directory
file = open(os.path.join(current_directory, 'DataFolder', 'Data.txt'), 'wb') #wb = write bytes because we are saving or writing
dataToSave = [1, 'foo', '2', 43]

pickle.dump(dataToSave, file) #We first give it the data to save, then the file to save it to

The pickle.load module works similarly. Here is how it works -

from pathlib import Path
import os, pickle
current_directory = Path(__file__).parent #Get current directory
file = open(os.path.join(current_directory, 'DataFolder', 'Data.txt'), 'rb') #rb = read bytes because we are reading the file

loadedData = pickle.load(file) #We give it the file and it loads in everything from the file. That data is the loaded as the variable loadedData

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Hope there aren't any mistakes in there

And so that it's in this thread - JSON covers a huge fraction of serialization needs.