Python – Convert a python dict to a string and back

dictionaryjsonpythonserialization

I am writing a program that stores data in a dictionary object, but this data needs to be saved at some point during the program execution and loaded back into the dictionary object when the program is run again.
How would I convert a dictionary object into a string that can be written to a file and loaded back into a dictionary object? This will hopefully support dictionaries containing dictionaries.

Best Solution

The json module is a good solution here. It has the advantages over pickle that it only produces plain text output, and is cross-platform and cross-version.

import json
json.dumps(dict)

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Javascript – Safely turning a JSON string into an object

JSON.parse(jsonString) is a pure JavaScript approach so long as you can guarantee a reasonably modern browser.

Python – How to execute a program or call a system command

Use the subprocess module in the standard library:

import subprocess
subprocess.run(["ls", "-l"])

The advantage of subprocess.run over os.system is that it is more flexible (you can get the stdout, stderr, the "real" status code, better error handling, etc...).

Even the documentation for os.system recommends using subprocess instead:

The subprocess module provides more powerful facilities for spawning new processes and retrieving their results; using that module is preferable to using this function. See the Replacing Older Functions with the subprocess Module section in the subprocess documentation for some helpful recipes.

On Python 3.4 and earlier, use subprocess.call instead of .run:

subprocess.call(["ls", "-l"])

Best Solution

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Javascript – Safely turning a JSON string into an object

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