在 Python 中加载 JSON 文件会引发错误。

Question

I am fetching an API from url like: http://api.example.com/search/foo/bar

using this simple code.

import json
url = "http://api.example.com/search/foo/bar"
result = json.loads(url)  # result is now a dict
print result['name']

But, I am getting this error.

Traceback (most recent call last):
  File "index.py", line 6, in <module>
    result = json.loads(url);
  File "/usr/lib64/python2.7/json/__init__.py", line 338, in loads
    return _default_decoder.decode(s)
  File "/usr/lib64/python2.7/json/decoder.py", line 365, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
  File "/usr/lib64/python2.7/json/decoder.py", line 383, in raw_decode
    raise ValueError("No JSON object could be decoded")
ValueError: No JSON object could be decoded

Answer 1

You need to read the data from the url first. json.loads() loads the json from a string. But that string is essentially just the json structure in string form. You need to get that json string by reading the data from that url request, which should be the json string.

For instance, something like this:

import json
import urllib2
url = "http://api.example.com/search/foo/bar"
response = urllib2.urlopen(url)
json_string = response.read()

json_string now contains the json you seek, assuming that the api call returns it correctly.

json_dict = json.loads(json_string)

You should be able to access the items in the json with json_dict['name'] etc.

json.loads() loads the json from a string, which is what is done above(and why I used read() to get the string). json.load() loads from a json object. If the api is returning a pure json format as you mentioned in the comments, you could try this instead:

response = urllib2.urlopen(url)
json_dict = json.load(response)