Reading JSON from a file?

问题:

I am getting a bit of headache just because a simple looking, easy statement is throwing some errors in my face.

I have a json file called strings.json like this:

\"strings\": [{\"-name\": \"city\", \"#text\": \"City\"}, {\"-name\": \"phone\", \"#text\": \"Phone\"}, ...,
            {\"-name\": \"address\", \"#text\": \"Address\"}]

I want to read the json file, just that for now. I have these statements which I found out, but it\'s not working:

import json
from pprint import pprint

with open(\'strings.json\') as json_data:
    d = json.load(json_data)
    json_data.close()
    pprint(d)

The error displayed on the console was this:

Traceback (most recent call last):
File \"/home/.../android/values/manipulate_json.py\", line 5, in <module>
d = json.loads(json_data)
File \"/usr/lib/python2.7/json/__init__.py\", line 326, in loads
return _default_decoder.decode(s)
File \"/usr/lib/python2.7/json/decoder.py\", line 366, in decode
obj, end = self.raw_decode(s, idx=_w(s, 0).end())
TypeError: expected string or buffer
[Finished in 0.1s with exit code 1]

Edited

Changed from json.loads to json.load

and got this:

Traceback (most recent call last):
File \"/home/.../android/values/manipulate_json.py\", line 5, in <module>
d = json.load(json_data)
File \"/usr/lib/python2.7/json/__init__.py\", line 278, in load
**kw)
File \"/usr/lib/python2.7/json/__init__.py\", line 326, in loads
return _default_decoder.decode(s)
File \"/usr/lib/python2.7/json/decoder.py\", line 369, in decode
raise ValueError(errmsg(\"Extra data\", s, end, len(s)))
ValueError: Extra data: line 829 column 1 - line 829 column 2 (char 18476 - 18477)
[Finished in 0.1s with exit code 1]

回答1:

The json.load() method (without \"s\" in \"load\") can read a file directly:

import json

with open(\'strings.json\') as json_data:
    d = json.load(json_data)
    print(d)

You were using the json.loads() method, which is used for string arguments only.

Edit: The new message is a totally different problem. In that case, there is some invalid json in that file. For that, I would recommend running the file through a json validator.

There are also solutions for fixing json like for example How do I automatically fix an invalid JSON string?.

回答2:

Here is a copy of code which works fine for me

import json

with open(\"test.json\") as json_file:
    json_data = json.load(json_file)
    print(json_data)

with the data

{
    \"a\": [1,3,\"asdf\",true],
    \"b\": {
        \"Hello\": \"world\"
    }
}

you may want to wrap your json.load line with a try catch because invalid JSON will cause a stacktrace error message.

回答3:

The problem is using with statement:

with open(\'strings.json\') as json_data:
    d = json.load(json_data)
    pprint(d)

The file is going to be implicitly closed already. There is no need to call json_data.close() again.

回答4:

In python 3, we can use below method.

Read from file and convert to JSON

import json

# Considering \"json_list.json\" is a json file

with open(\'json_list.json\') as fd:
     json_data = json.load(fd)

or

import json

json_data = json.load(open(\'json_list.json\'))

Using with statement will automatically close the opened file descriptor.

String to JSON

import json

json_data = json.loads(\'{\"name\" : \"myName\", \"age\":24}\')

回答5:

To add on this, today you are able to use pandas to import json:
https://pandas.pydata.org/pandas-docs/stable/generated/pandas.read_json.html You may want to do a careful use of the orient parameter.