How to save and load data from files using pickle

[SheeppOSU]

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 -

1 2	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 -

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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 -

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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 -

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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

[metulburr]

https://www.benfrederickson.com/dont-pickle-your-data/

[micseydel]

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