CODEWITHSUNDEEP
pythonjsonpython-3.xstr-replace
rahaf
rahaf

Reputation: 13

modifying JSON value

I'm trying to modify a value in a JSON file, I tried the following code but it is not changing anything so I'm not sure what I'm doing wrong... 

def file_filtering(file):
    with open(file, 'r') as f:
        data = json.load(f)
        f.close()
    for elem in data['features']:
        elem = elem[:-1]
    with open(file, 'w') as f:
        json.dump(data, f, indent=4, separators=(',', ': '), sort_keys=False)
        f.close()

I'm trying to change the URL by simply removing the last character '/', without deleting the values under the URL. 

 "features": {
        "https://services.runescape.com-ow.top/weblogin/loginForm/": {
            "activex_count": 0,
            "addeventlistener_count": 0,
            "alert_count": 0,
        }
}

Upvotes: 1

Views: 44

Answers (1)

filbranden
filbranden

Reputation: 8898

The problem you're having is that elem = elem[:-1] is simply changing the elem variable and not really changing the key of the dictionary.

Generally, changing a key from a dictionary in place is hard... It's much easier to just create a new dictionary altogether. You can do so with a dict comprehension, such as:

{key[:-1]: value for key, value in data['features'].items()}

Which you can replace in the JSON data with:

data['features'] = {
    key[:-1]: value
    for key, value in data['features'].items()}

You can do slightly better, rather than chopping the last character of the key, you can explicitly strip it of slashes at the end, using rstrip():

data['features'] = {
    key.rstrip('/'): value
    for key, value in data['features'].items()}

Putting it all together:

with open(file, 'r') as f:
    data = json.load(f)
data['features'] = {
    key.rstrip('/'): value
    for key, value in data['features'].items()}
with open(file, 'w') as f:
    json.dump(data, f, indent=4, separators=(',', ': '), sort_keys=False)

Note that you don't need to call f.close() explicitly, opening a file in a context manager (as the with statement does) takes care of closing it automatically once you leave it.

Upvotes: 2

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