Keeping the data of a variable between runs of code

Question

For a school project I am making a hangman game in Python. Right now my code picks a word from a dictionary like so:

WordList = ["cat", "hat", "jump", "house", "orange", "brick", "horse", "word"]
word = WordList[random.randint(0, len(WordList) - 1)]

right now the list of words has to be set within the code before running it, but I added the ability to add words to the list while running it:

if command == "add":
    while True:
        print("type a word to add to the dictionary")
        print("type /b to go back to game")
        add = raw_input("word: ")

        if add != "/b":
            WordList = WordList + [add]

            print add, "added!"
        else:
            print("returning to game")
            break

however, once I exit the code, the added words are obviously not saved, so I would either have to manually add all the words to the list, or add a bunch of words to the list once the code starts every time. so I am wondering if there is a simple way that I can have the variable save after the code is finished, so that WordList will keep the added words next time the code starts. the program I use to write python is Jetbrains PyCharm, if that makes a difference. Apologies for any un-optimal code, I'm new to code.

Answer 1

Simply pickle the data you want to keep persistent. Since your use case doesn't require very complex data storage, pickling is a very good option. A small example:

import pickle

word_list = ["cat", "hat", "jump", "house", "orange", "brick", "horse", "word"]

# do your thing here, like
word_list.append("monty")

# open a pickle file
filename = 'mypickle.pk'

with open(filename, 'wb') as fi:
    # dump your data into the file
    pickle.dump(word_list, fi)

Later when you need to use it again, just load it up:

# load your data back to memory when you need it
with open(filename, 'rb') as fi:
    word_list = pickle.load(fi)

Ta-da! You have data persistence now. More reading here. A few important pointers:

1. Notice the 'b' when I use open() to open a file. Pickles are commonly stored in a binary format, so you must open the file in a binary mode.
2. I used the with context manager. This ensures that a file is safely closed once all my work with the file is done.