Correct way of loading JSON from file into a Python dictionary

Question

I am currently doing this to save JSON to a file:

with open(filename, 'w+') as f:
    json.dump(data, f)

and I am doing this to load JSON from a file into a Python dictionary:

with open(filename, 'r') as f:
     data = json.loads(json.load(f))

I understand that json.load loads JSON from a file and json.loads loads JSON from a string.

When I call json.load(f) to load the JSON from file I get a string representation of the JSON object:

'{"a": 1,"b": 2,"c": 3}'

I then call json.loads(json.load(f)) to convert that string representation to a Python dictionary:

{'a': 1, 'b': 2, 'c': 3}

I understand that I can also use ast.literal_eval() to convert the string into a Python dictionary.

My question is - what is the correct way of loading JSON from a file directory into a Python dictionary? is it really necessary to call both json.loads and json.load to get JSON from a file into a dictionary?

Answer 1

Your data must have already been a JSON string to begin with and then you double-encoded it during the json.dump. Then of course you need to double-decode it later. So instead of encoding the original JSON with JSON again, just write it to the file as-is:

with open(filename, 'w+') as f:
    f.write(data)