Python json.loads shows ValueError: Extra data

Iterate over the file, loading each line as JSON in the loop:

tweets = []
for line in open('tweets.json', 'r'):
    tweets.append(json.loads(line))

This avoids storing intermediate python objects. As long as you write one full tweet per append() call, this should work.

This may also happen if your JSON file is not just 1 JSON record.
A JSON record looks like this:

[{"some data": value, "next key": "another value"}]

It opens and closes with a bracket [ ], within the brackets are the braces { }. There can be many pairs of braces, but it all ends with a close bracket ].
If your json file contains more than one of those:

[{"some data": value, "next key": "another value"}]
[{"2nd record data": value, "2nd record key": "another value"}]

then loads() will fail.

I verified this with my own file that was failing.

import json

guestFile = open("1_guests.json",'r')
guestData = guestFile.read()
guestFile.close()
gdfJson = json.loads(guestData)

This works because 1_guests.json has one record []. The original file I was using all_guests.json had 6 records separated by newline. I deleted 5 records, (which I already checked to be bookended by brackets) and saved the file under a new name. Then the loads statement worked.

Error was

   raise ValueError(errmsg("Extra data", s, end, len(s)))
ValueError: Extra data: line 2 column 1 - line 10 column 1 (char 261900 - 6964758)

PS. I use the word record, but that’s not the official name. Also, if your file has newline characters like mine, you can loop through it to loads() one record at a time into a json variable.

I came across this because I was trying to load a JSON file dumped from MongoDB. It was giving me an error

JSONDecodeError: Extra data: line 2 column 1

The MongoDB JSON dump has one object per line, so what worked for me is:

import json
data = [json.loads(line) for line in open('data.json', 'r')]

If you want to solve it in a two-liner you can do it like this:

with open('data.json') as f:
    data = [json.loads(line) for line in f]

One-liner for your problem:

data = [json.loads(line) for line in open('tweets.json', 'r')]

I think saving dicts in a list is not an ideal solution here proposed by @falsetru.

Better way is, iterating through dicts and saving them to .json by adding a new line.

Our 2 dictionaries are

d1 = {'a':1}

d2 = {'b':2}

you can write them to .json

import json
with open('sample.json','a') as sample:
    for dict in [d1,d2]:
        sample.write('{}n'.format(json.dumps(dict)))

And you can read json file without any issues

with open('sample.json','r') as sample:
    for line in sample:
        line = json.loads(line.strip())

Simple and efficient

I just got the same error while my json file is like this

{"id":"1101010","city_id":"1101","name":"TEUPAH SELATAN"}
{"id":"1101020","city_id":"1101","name":"SIMEULUE TIMUR"}

And I found it malformed, so I changed it to:

{
  "datas":[
    {"id":"1101010","city_id":"1101","name":"TEUPAH SELATAN"},
    {"id":"1101020","city_id":"1101","name":"SIMEULUE TIMUR"}
  ]
}

My json file was formatted exactly as the one in the question but none of the solutions here worked out. Finally I found a workaround on another Stackoverflow thread. Since this post is the first link in Google search, I put the that answer here so that other people come to this post in the future will find it more easily.

As it’s been said there the valid json file needs "[" in the beginning and "]" in the end of file. Moreover, after each json item instead of "}" there must be a "},". All brackets without quotations! This piece of code just modifies the malformed json file into its correct format.

https://stackoverflow.com/a/51919788/2772087

The error is due to the nsymbol if you use the read()method of the file descriptor… so don’t bypass the problem by using readlines()& co but just remove such character!

import json

path = # contains for example {"c": 4} also on multy-lines

new_d = {'new': 5}
with open(path, 'r') as fd:
    d_old_str = fd.read().replace('n', '') # remove all n
    old_d = json.loads(d_old_str)

# update new_d (python3.9 otherwise new_d.update(old_d))
new_d |= old_d
          
with open(path2, 'w') as fd:
    fd.write(json.dumps(new_d)) # save the dictionary to file (in case needed)

… and if you really really want to use readlines() here an alternative solution

new_d = {'new': 5}
with open('some_path', 'r') as fd:
    d_old_str = ''.join(fd.readlines()) # concatenate the lines
    d_old = json.loads(d_old_str)

# then as above

If your data is from a source outside your control, use this

def load_multi_json(line: str) -> [dict]:
    """
    Fix some files with multiple objects on one line
    """
    try:
        return [json.loads(line)]
    except JSONDecodeError as err:
        if err.msg == 'Extra data':
            head = [json.loads(line[0:err.pos])]
            tail = FrontFile.load_multi_json(line[err.pos:])
            return head + tail
        else:
            raise err