Editing Newest JSON File In A Directory

June 21, 2019 | 1 Minute Read

This post shows how to edit the newest (by create date) JSON file from a Windows directory.

In this example, we are using Python 3.6.

First, we have to load the needed libraries.

from stat import S_ISREG, ST_CTIME, ST_MODE
import os, time
import json

Then, we have to get all JSON files from a directory. Replace the directory here with the directory you want.

directory = "C:/Users/tiewkeehui/JsonFiles/"
entries = (os.path.join(directory, fn) for fn in os.listdir(directory) if fn.endswith('.json'))
entries = ((os.stat(path), path) for path in entries)

Then we add the stats of all the files

entries = ((stat[ST_CTIME], path) for stat, path in entries if S_ISREG(stat[ST_MODE]))

S_ISREG checks if the file is a normal file (ex. not a directory). It will return a non-zero value if it is a regular file.

Now we get the latest created JSON file

json_file_path = sorted(entries)[-1][1]

Last but not least, we open and load the JSON file and add our new key-value pair. After that, we overwrite the existing file.

with open(json_file_path, encoding="utf-8-sig") as json_file:
    data = json.load(json_file)
    data['new_key'] = new_value

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

References:

1. https://docs.python.org/3.6/library/stat.html
2. https://stackoverflow.com/questions/40163270/what-is-s-isreg-and-what-does-it-do
3. https://en.wikipedia.org/wiki/Stat_(system_call)
4. https://stackoverflow.com/a/539024