I am using fastjsonschema for validating json records against its schema.
Some thing like this:
import fastjsonschema
validate = fastjsonschema.compile({'type': 'string'})
validate('hello')
If the json is valid, it returns the json string else return the error string. I just want to check if the json is valid or not. For this I can do a workaround of comparing output of the validate method and the json input.
But I want something cleaner. May be something like '$?' in unix or something better.
Could you suggest me?
From the documentation, there seem to be two different exceptions thrown in case of error:
JsonSchemaDefinitionException, when the definition is bad
JsonSchemaException, when the data is not matching the definition
In Python, you can simply wrap that with a try ... except block like this:
try:
validate = fastjsonschema.compile({'type': 'string'})
validate(1)
except (fastjsonschema.JsonSchemaException, fastjsonschema.JsonSchemaDefinitionException):
print("Uh oh ...")
Related
Im getting a response from a request to my power plug that looks like this:
{"emeter":{"get_realtime":{"voltage_mv":235176,"current_ma":12,"power_mw":0,"total_wh":4525,"err_code":0}}}
Which I saved to the variable response
Now I want it to just give me the value of "current_ma" when I am sending the request.
How can I achieve this?
I tried something like response.current_ma, but that just gives me errors.
Like this:
response["emeter"]["get_realtime"]["current_ma"]
JSON is like a tree structure, where you need to reference the levels in the tree to where the data you are fetching is located.
I believe its good practice to wrap this in a try, in case the value is not present. Like this:
try:
my_var = response["emeter"]["get_realtime"]["current_ma"]
except KeyError as ex:
# do something useful if exception is thrown
You can use below code:
current_ma = response["emeter"]["get_realtime"]["current_ma"]
print("Antwort: {}".format(response["emeter"]["get_realtime"]["current_ma"]))
I am trying to read a json which includes a number of tweets, but I get the following error.
OverflowError: int too large to convert
The script filters multiple json files to get specific tweets, and it crashes when reaching to a specific json.
The line that creates the error is this one :
df_temp = pd.read_json(path_or_buf=json_path, lines=True)
Here is the error in the cmd
Just store the user id as a String, and treat it like it is one (this is actually what you should do when dealing with this kind of ids). If you can't change the json input format, you can always parse it like a string before parsing it like a json object, and add the quotes to the id code, using for instance regexes: Regex in python.
I don't know with which library you are parsing the json, but maybe also implicit casting will work: either try the "getString" method on the number instead of the "getInt" method, or force python to treat the object like a string, with something like x = "" + json.getId()
Python is pretty loose on typing and may let you do it.
I have the following code..
.... rest api call >> response
rsp = response.json()
print json2html.convert(rsp)
which results in the following
error: Can't convert NULL!
I therefore started looking into schemes to replace all None / Null's in my JSON response, but I'm having an issue since the JSON returned from the api is complex and nested many levels and I don't know where the NULL will actually appear.
From what I can tell I need to iterate over the dictionary objects recursively and check for any values that are NONE and actually rebuild the object with the values replaced, but I don't really know where to start since dictionary objects are immutable..
If you look at json2html's source it seems like you have a different problem - and the error message is not helping.
Try to use it like this:
print json2html.convert(json=rsp)
btw. because I've already contributed to that project a bit I've opened up the following PR due to this question: https://github.com/softvar/json2html/pull/20
I don't have much experience in Python and I've ran into problem converting sql query data which is technically a list containing a JSON string into a Python dictionary. I'm querying the sqlite3 database which is returning a piece of data like this:
def get_answer(self, id):
self.__cur.execute('select answer from some_table where id= %s;' % id)
res_data = self.__cur.fetchall()
return res_data
The data is a single JSON format element which its simplified version looks like this:
[
{"ind": [ {"v": 101}, {"v": 102}, {"v": 65 }]},
{"ind": [ {"v": 33}, {"v": 102}, {"v": 65}]}
]
But when I try to convert the res_data to JSON, with code like this:
temp_json = simplejson.dumps(get_answer(trace_id))
it returns a string and when I get the len(temp_json) it returns the number of characters in res_data instead of the number of objects in res_data. However, if I use Visual Studio's JSON visualizer on what get_answer(trace_id) returns, it properly shows each of the objects res_data.
I also tried to convert the res_data to a dictionary with code like this:
dict_data = ast.literal_eval(Json_data)
or
dict_data = ast.literal_eval(Json_data[0])
and in both cases it throws a "malformed string" exception. I tried to write it to a file and read it back as a JSON but it didn't worked.
Before doing that I had the copy pasted the res_data manually and used:
with open(file_name) as json_file:
Json_data = simplejson.load(json_file)
and it worked like a charm. I've been experimenting different ways stated in SO and elsewhere but although the problem seems very straight forward, I still haven't found a solution so your help is highly appreciated.
OK, I finally found the solution:
states = json.loads(temp_json[0][0])
one confusing issue was that states = json.loads(temp_json[0]) was throwing the "Expected string or buffer" exception and temp_json was a list containing only one element, so I didn't think I will get anything from temp_json[0][0].
I hope it helps others too!
I think you are confusing the data formats. What you supposedly get back from your database wrapper seems to be a list of dictionaries (it is not SQL either - your question title is misleading). But I actually think that sqlite3 would give you a list of tuples.
JSON is a text format or more precisely the serialization of an object to a string. That's why json.dumps (= dump to string) results in a string and json.loads(= load string) would result in a python object, a dictionary or a list of dictionaries).
json.dumps does NOT mean "dump JSON to string". It is rather the .dumps method of the json module which takes a Python object (dict, list) and serializes it to JSON.
I will extend the answer if I understand what exactly you want to achieve but you get JSON with json.dumps(), JSON is a string format. In contrast simplejson.load() gives you a Python list or dict.
Did you try json.loads() just in case the return from your database is actually a string (which you could easily test).
Warning: I'm a total newbie; apologies if I didn't search for the right thing before submitting this question. I found lots on how to ignore errors, but nothing quite like what I'm trying to do here.
I have a simple script that I'm using to grab data off a database, parse some fields apart, and re-write the parsed values back to the database. Multiple users are submitting to the database according to a delimited template, but there is some degree of non-compliance, meaning sometimes the string won't contain all/any delimiters. My script needs to be able to handle those instances by throwing them out entirely.
I'm having trouble throwing out non-compliant strings, rather than just ignoring the errors they raise. When I've tried try-except-pass, I've ended up getting errors when my script attempts to append parsed values into the array I'm ultimately writing back to the db.
Originally, my script said:
def parse_comments(comments):
parts = comments.split("||")
if len(parts) < 20:
raise ValueError("Comment didn't have enough || delimiters")
return Result._make([parts[i].strip() for i in xrange(2, 21, 3)])
Fully compliant uploads would append Result to an array and write back to db.
I've tried try/except:
def parse_comments(comments):
parts = comments.split("||")
try:
Thing._make([parts[i].strip() for i in xrange(2, 21, 3)])
except:
pass
return Thing
But I end up getting an error when I try and append the parsed values to an array -- specifically TypeError: 'type' object has no attribute 'getitem'
I've also tried:
def parse_comments(comments):
parts = comments.split("||")
if len(parts) >= 20:
Thing._make([parts[i].strip() for i in xrange(2, 21, 3)])
else:
pass
return Thing
but to no avail.
tl;dr: I need to parse stuff and append parsed items. If a string can't be parsed how I want it, I want my code to ignore that string entirely and move on.
But I end up getting an error when I try and append the parsed values to an array -- specifically TypeError: 'type' object has no attribute 'getitem'
Because Thing means the Thing class itself, not an instance of that class.
You need to think more clearly about what you want to return when the data is invalid. It may be the case that you can't return anything directly usable here, so that the calling code has to explicitly check.
I am not sure I understand everything you want to do. But I think you are not catching the error at the right place. You said yourself that it arose when you wanted to append the value to an array. So maybe you should do:
try:
# append the parsed values to an array
except TypeError:
pass
You should give the exception type to catch after except, otherwise it will catch any exception, even a user's CTRL+C which raise a KeyboardInterrupt.