如何通过python在json中写入或附加对象的特定键/值

Question

The question is very self explanatory. I need to write or append at a specific key/value of an object in json via python.

I'm not sure how to do it because I'm not good with JSON but here is an example of how I tried to do it (I know it is wrong).

with open('info.json', 'a') as f:
    json.dumps(data, ['key1'])

this is the json file:

{"key0":"xxxxx@gmail.com","key1":"12345678"}

Answer 1

A typical usage pattern for JSONs in Python is to load the JSON object into Python, edit that object, and then write the resulting object back out to file.

import json

with open('info.json', 'r') as infile:
    my_data = json.load(infile)
    
my_data['key1'] = my_data['key1'] + 'random string'
# perform other alterations to my_data here, as appropriate ...

with open('scratch.json', 'w') as outfile:
    json.dump(my_data, outfile)

Contents of 'info.json' are now

{"key0": "xxxxx@gmail.com", "key1": "12345678random string"}

The key operations were json.load(fp) , which deserialized the file into a Python object in memory, and json.dump(obj, fp) , which reserialized the edited object to the file being written out.

This may be unsuitable if you're editing very large JSON objects and cannot easily pull the entire object into memory at once, but if you're just trying to learn the basics of Python's JSON library it should help you get started.

Answer 2

An example for appending data to a json file using json library:

import json

raw =  '{ "color": "green",  "type": "car" }'
data_to_add = { "gear": "manual" }  
parsed = json.loads(raw) 
parsed.update(data_to_add) 

You can then save your changes with json.dumps .