The json.load() method (without "s" in "load") can read a file directly:
import json
with open('strings.json') as f:
d = json.load(f)
print(d)
You were using the json.loads() method, which is used for string arguments only.
The error you get with json.loads is a totally different problem. In that case, there is some invalid JSON content 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?.
Answer from ubomb on Stack OverflowVideos
The json.load() method (without "s" in "load") can read a file directly:
import json
with open('strings.json') as f:
d = json.load(f)
print(d)
You were using the json.loads() method, which is used for string arguments only.
The error you get with json.loads is a totally different problem. In that case, there is some invalid JSON content 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?.
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.
Can someone explain what the difference is between using either load() or loads() is with the JSON library? And which, if either, is the preferred method.
I'm writing a simple script where I want the JSON data from a URL parsed out into a list. Both of these options seem to work:
import json import urllib2 url = "string to url" response = urllib2.urlopen(url) data = json.load(response)
or
import json import urllib2 url = "string to url" response = urllib2.urlopen(url) data = json.loads(response.read())
I know that there are other libraries available for parsing out JSON data, but for the time being I'm working only with the json and urllib2 libraries.
Any insight into which one should be used?
Thanks
load() loads JSON from a file or file-like object
loads() loads JSON from a given string or unicode object
It's in the documentation
The "s" is an abbreviation for "string". "dump__s__" is read as "dump string". "load__s__" = "load string". Otherwise these methods want a file-like object. This convention is scattered throughout python and even 3rd-party packages.
You have a JSON Lines format text file. You need to parse your file line by line:
import json
data = []
with open('file') as f:
for line in f:
data.append(json.loads(line))
Each line contains valid JSON, but as a whole, it is not a valid JSON value as there is no top-level list or object definition.
Note that because the file contains JSON per line, you are saved the headaches of trying to parse it all in one go or to figure out a streaming JSON parser. You can now opt to process each line separately before moving on to the next, saving memory in the process. You probably don't want to append each result to one list and then process everything if your file is really big.
If you have a file containing individual JSON objects with delimiters in-between, use How do I use the 'json' module to read in one JSON object at a time? to parse out individual objects using a buffered method.
In case you are using pandas and you will be interested in loading the json file as a dataframe, you can use:
import pandas as pd
df = pd.read_json('file.json', lines=True)
And to convert it into a json array, you can use:
df.to_json('new_file.json')
Yes, s stands for string. The json.loads function does not take the file path, but the file contents as a string. Look at the documentation.
Simple example:
with open("file.json") as f:
data = json.load(f) # ok
data = json.loads(f) # not ok, f is not a string but a file
text = '{"a": 1, "b": 2}' # a string with json encoded data
data = json.loads(text)
Just going to add a simple example to what everyone has explained,
json.load()
json.load can deserialize a file itself i.e. it accepts a file object, for example,
# open a json file for reading and print content using json.load
with open("/xyz/json_data.json", "r") as content:
print(json.load(content))
will output,
{u'event': {u'id': u'5206c7e2-da67-42da-9341-6ea403c632c7', u'name': u'Sufiyan Ghori'}}
If I use json.loads to open a file instead,
# you cannot use json.loads on file object
with open("json_data.json", "r") as content:
print(json.loads(content))
I would get this error:
TypeError: expected string or buffer
json.loads()
json.loads() deserialize string.
So in order to use json.loads I will have to pass the content of the file using read() function, for example,
using content.read() with json.loads() return content of the file,
with open("json_data.json", "r") as content:
print(json.loads(content.read()))
Output,
{u'event': {u'id': u'5206c7e2-da67-42da-9341-6ea403c632c7', u'name': u'Sufiyan Ghori'}}
That's because type of content.read() is string, i.e. <type 'str'>
If I use json.load() with content.read(), I will get error,
with open("json_data.json", "r") as content:
print(json.load(content.read()))
Gives,
AttributeError: 'str' object has no attribute 'read'
So, now you know json.load deserialze file and json.loads deserialize a string.
Another example,
sys.stdin return file object, so if i do print(json.load(sys.stdin)), I will get actual json data,
cat json_data.json | ./test.py
{u'event': {u'id': u'5206c7e2-da67-42da-9341-6ea403c632c7', u'name': u'Sufiyan Ghori'}}
If I want to use json.loads(), I would do print(json.loads(sys.stdin.read())) instead.