I've written some code that converts a JSON object to an iCalendar (.ics) object and now I am trying to test it. The problem is that I can't figure out how to create a generic JSON object to use as the parameter. Some of my attempts are as follows:
# 1
obj_json = u'sample json data in string form'
obj = json.loads(obj_json)
# 2
# I'm not sure about this very first line. My supervisor told me to put it in but he
# has a very heavy accent so I definitely could have heard him incorrectly.
input.json
with open('input.json') as f:
obj = json.loads(f.read())
Try,
import json
some_dict = {'id': 0123, 'text': 'A dummy text'}
dummy_json = json.dumps(some_dict)
Now, feed your dummy json to your function. i.e.
'{"text": "A dummy text", "id": 83}'
You can do dumps with a string object too.
See pnv's answer, but you probably don't need to dump it. Just use a dictionary, as pnv did, and pass that into whatever you need to. Unless you are about to pass your json object over the wire to something, I don't know why you'd want to dump it.
I would've added this as a comment, but no rep, yet. :)
Related
Im trying to retrieve data from a database named RethinkDB, they output JSON when called with r.db("Databasename").table("tablename").insert([{ "id or primary key": line}]).run(), when doing so it outputs [{'id': 'ValueInRowOfid\n'}] and I want to parse that to just the value eg. "ValueInRowOfid". Ive tried with JSON in Python, but I always end up with the typeerror: list indices must be integers or slices, not str, and Ive been told that it is because the Database outputs invalid JSON format. My question is how can a JSON format be invalid (I cant see what is invalid with the output) and also what would be the best way to parse it so that the value "ValueInRowOfid" is left in a Operator eg. Value = ("ValueInRowOfid").
This part imports the modules used and connects to RethinkDB:
import json
from rethinkdb import RethinkDB
r = RethinkDB()
r.connect( "localhost", 28015).repl()
This part is getting the output/value and my trial at parsing it:
getvalue = r.db("Databasename").table("tablename").sample(1).run() # gets a single row/value from the table
print(getvalue) # If I print that, it will show as [{'id': 'ValueInRowOfid\n'}]
dumper = json.dumps(getvalue) # I cant use `json.loads(dumper)` as JSON object must be str. Which the output of the database isnt (The output is a list)
parsevalue = json.loads(dumper) # After `json.dumps(getvalue)` I can now load it, but I cant use the loaded JSON.
print(parsevalue["id"]) # When doing this it now says that the list is a str and it needs to be an integers or slices. Quite frustrating for me as it is opposing it self eg. It first wants str and now it cant use str
print(parsevalue{'id'}) # I also tried to shuffle it around as seen here, but still the same result
I know this is janky and is very hard to comprehend this level of stupidity that I might be on. As I dont know if it is the most simple problem or something that just isnt possible (Which it should or else I cant use my data in the database.)
Thank you for reading this through and not jumping straight into the comments and say that I have to read the JSON documentation, because I have and I havent found a single piece that could help me.
I tried reading the documentation and watching tutorials about JSON and JSON parsing. I also looked for others whom have had the same problems as me and couldnt find.
It looks like it's returning a dictionary ({}) inside a list ([]) of one element.
Try:
getvalue = r.db("Databasename").table("tablename").sample(1).run()
print(getvalue[0]['id'])
Studying Python, I am following an excellent Corey Schafer tutorial on Flask, he does this (I have extracted and summarized it for obvious reasons):
from folder_app import app # I did it to follow the structure and that the code is equal to the original
s = Serializer(app.config['SECRET_KEY'], 1800) # key, seconds
token = s.dumps({'user_id': 1}).decode('utf-8')
s = Serializer(app.config['SECRET_KEY'])
user_id = s.loads(token)['user_id'] # This is where I have the doubt
print(user_id)
print(type(s.loads(token)))
The code works, the problem I have is that although as you can see (s.loads (token)) is a dict, I expected to see something like this s.loads ({token ['user_id']}), or s.loads (token ['user_id']) or something like that. That is, it is a dict but it does not seem so. And my doubt goes in the sense if this comes from a greater concept of those they call "pythonic" (which I have not seen so far), or is something that only happens particularly as in this case. Incidentally, https://itsdangerous.palletsprojects.com/en/1.1.x/jws/ this appears: loads (self, s, salt = None, return_header = False) the arguments are in parentheses. I hope it is clear what my doubt is :)
I know this is not answer per say but just to add to my comment. This is an example of how the loads function works on dictionaries with the json module. https://docs.python.org/3/library/json.html#json.loads. What it does is take a json string and return the dictionary type object in Python. Your Serializer is doing something similar. It takes the token string and represents it as an object like dict
The s.dumps I am assuming is similar to json.dumps which gives you the json string representation of python dictionary.
import json
my_dict = json.loads('{"user_id": "Mane", "name": "Joe"}')
my_dict['user_id']
So you could just do json.loads('{"user_id": "Mane", "name": "Joe"}')['user_id'] which is just chaining the operations.
I have to build, in python, an address book of contacts using a json file. So, I have to define a class Contact which has as attributes hust the name, surname and mail. In the solution there is a function that I never would have thought of: jsonify(self). I don't understand what it does and why I need it. Someone can help me figure it out?
def jsonify(self):
contact = {'name':self.name,'surname':self.surname,'mail':self.mail}
return contact
Using the json library, you can convert objects into JSON really easily, but it needs to know how to go about converting them. The library doesn't know how to interpret your custom class:
>>> import json
>>> contact = Contact("Hello", "World", "hello#world.com")
>>> contact_json = json.dumps(contact)
TypeError: Object of type 'Contact' is not JSON serializable
(json.dumps(obj) converts its input to JSON and returns it as a string. You can also do json.dump(obj, file_handle) to save it to a file).
A dictionary is a known type in Python, so the json library knows how to convert it into json format:
>>> import json
>>> contact = Contact("Hello", "World", "hello#world.com")
>>> contact_json = json.dumps(contact.jsonify())
{
"name": "Hello",
"surname": "World",
"mail": "hello#world.com"
}
Using that jsonify method, you're converting the fields from your class into something that the json library can understand and knows how to translate.
This is a quick and easy way to serialise your object into JSON, but isn't necessarily the best way to do it - ideally you'd tell the JSON library how to interpret your class (see this related question: How to make a class JSON serializable).
Edit: Seeing the comment discussion - I'm assuming here you have an understanding of Python data structures and classes. If this is not the case it's worth reading up on those first.
I'm using the Google Visualization Library for python (gviz) to generate chart objects. This works great for generating JSON that can be read by the Google Charts using the DataTable.ToJSon method. What I'm trying to do now, however, is add multiple Google Chart data tables to one JSON dictionary. In other words, what I'm making now is this:
Chart_Data = JSON_Chart_Data_1
and what I want to make is this:
Chart_Data = {'Chart_1' : JSON_Chart_Data_1,
'Chart_2' : JSON_Chart_Data_2,}
Where Chart_Data is converted into a JSON string in both cases.
I'm pretty sure I can do this by converting the JSON string from gviz back into a python dictionary, compile the strings in a container dictionary as necessary, and then convert that container dictionary back into JSON, but that doesn't seem like a very elegant way to do it. Is there a better way? What I'm picturing is a .ToPythonObject method equivalent to .ToJSon, but there doesn't appear to be one in the library.
Thanks a lot,
Alex
I ended up doing my original, inelegant, solution to the problem with this function:
def CombineJson(JSON_List):
#Jsonlist should be a list of tuples, with the dictionary key and the json file to go with that.
#eg: [('json1', 'some json string'), ('json2', 'some other json string')]
Python_Dict = {}
for tup in JSON_List:
parsed_json = json.loads(tup[1])
Python_Dict[tup[0]] = parsed_json
BigJson = json.dumps(Python_Dict)
return BigJson
Thanks guys,
Alex
I have below JSON String. Now I want to extract each individual field from that JSON string.
So I decided to create a method parse_json which will accept a variable that I want to extract from the JSON String.
Below is my python script -
#!/usr/bin/python
import json
jsonData = '{"pp": [0,3,5,7,9], "sp": [1,2,4,6,8]}'
def parse_json(data):
jj = json.loads(jsonData)
return jj['+data+']
print parse_json('pp')
Now whenever I an passing pp to parse_json method to extract its value from the JSON String, I always get the error as -
return jj['+data+']
KeyError: '+data+'
Any idea how to fix this issue? As I need to pass the variable which I am supposed to extract from the JSON String?
You probably just want this:
return jj[data]
Your code is trying to look up a key named literally '+data+', when instead what you want to do is look up the key with a name of the function's parameter.
Just use data parameter itself.
Replace following line:
return jj['+data+'] # lookup with `+data+`, not `pp`
with:
return jj[data]