python - How to prettyprint a JSON file?

Question

I have a JSON file that is a mess that I want to prettyprint. What's the easiest way to do this in Python?

I know PrettyPrint takes an "object", which I think can be a file, but I don't know how to pass a file in. Just using the filename doesn't work.

Answer 1

The json module already implements some basic pretty printing with the indent parameter that specifies how many spaces to indent by:

>>> import json
>>>
>>> your_json = '["foo", {"bar":["baz", null, 1.0, 2]}]'
>>> parsed = json.loads(your_json)
>>> print(json.dumps(parsed, indent=4, sort_keys=True))
[
    "foo", 
    {
        "bar": [
            "baz", 
            null, 
            1.0, 
            2
        ]
    }
]

To parse a file, use json.load():

with open('filename.txt', 'r') as handle:
    parsed = json.load(handle)