如何使用python过滤文件中的json输出？

Question

We'd like to filter the following json output from testers.txt for any userid 's in list form:

{
    "status": true,
    "user": {
        "user_id": "16214222",
        "username": "tester11"
    }
},
{
    "status": true,
    "user": {
        "user_id": "44223333",
        "username": "tester22"
    }
}

What we currently have (tried old code):

import json

with open('testers.txt') as fp:
     inText = fp.read()
data = json.loads(inText)
print data['user_id']

Finally the output should be:

16214222,
44223333

We currently get the following error:

Traceback (most recent call last):
  File "start.py", line 5, in <module>
    data = json.loads(inText)
  File "/usr/lib/python2.7/json/__init__.py", line 339, in loads
    return _default_decoder.decode(s)
  File "/usr/lib/python2.7/json/decoder.py", line 367, in decode
    raise ValueError(errmsg("Extra data", s, end, len(s)))
ValueError: Extra data: line 7 column 2 - line 14 column 2 (char 105 - 212)

I'm new at stackoverflow - feel free to comment my question so I can improve myself.

Answer 1

You need a leading and trailing square bracket on your json file, like so:

[{
    "status": true,
    "user": {
        "user_id": "16214222",
        "username": "tester11"
    }
},
{
    "status": true,
    "user": {
        "user_id": "44223333",
        "username": "tester22"
    }
}]

And then you can do the following:

import json

with open('testers.txt') as fp:
    data = json.load(fp)

for user in data:
    print user['user']['user_id']

returning:

16214222
44223333

Answer 2

You will know the json is an invalid one upon using this website to validate the json.

You need to add a [] to make the json in a list of jsons as you json is not a valid one.

inText = '''
[{
    "status": true,
    "user": {
        "user_id": "16214222",
        "username": "tester11"
    }
},
{
    "status": true,
    "user": {
        "user_id": "44223333",
        "username": "tester22"
    }
}]
'''

import json

with open('testers.txt') as fp:
    inText = fp.read()
data = json.loads(inText)
print [d['user']['user_id'] for d in data]

Output:

[u'16214222', u'44223333']

Answer 3

use jq can achieve what you want easily.

# jq '.[] | .user | .user_id' testers.txt

"16214222"
"44223333"

assume you json in below format:

[{
    "status": true,
    "user": {
        "user_id": "16214222",
        "username": "tester11"
    }
},
{
    "status": true,
    "user": {
        "user_id": "44223333",
        "username": "tester22"
    }
}]