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How do I save a list in a file and read it as a list type?
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How do I save a list in a file and read it as a list type?
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Say I have the list score=[1,2,3,4,5] and it gets changed whilst my program is running. How could I save it to a file so that next time the program is run I can access the changed list as a list type?
I have tried:
score=[1,2,3,4,5]
with open("file.txt", 'w') as f:
for s in score:
f.write(str(s) + '\n')
with open("file.txt", 'r') as f:
score = [line.rstrip('\n') for line in f]
print(score)
But this results in the elements in the list being strings not integers.
You can use pickle module for that. This module have two methods,
- Pickling(dump): Convert Python objects into string representation.
- Unpickling(load): Retrieving original objects from stored string representstion.
https://docs.python.org/3.3/library/pickle.html code:
>>> import pickle
>>> l = [1,2,3,4]
>>> with open("test.txt", "wb") as fp: #Pickling
... pickle.dump(l, fp)
...
>>> with open("test.txt", "rb") as fp: # Unpickling
... b = pickle.load(fp)
...
>>> b
[1, 2, 3, 4]
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