While I am trying to retrieve values from JSON string, it gives me an error:
data = json.loads('{"lat":444, "lon":555}')
return data["lat"]
But, if I iterate over the data, it gives me the elements (lat and lon), but not the values:
data = json.loads('{"lat":444, "lon":555}')
ret = ''
for j in data:
ret = ret + ' ' + j
return ret
Which returns: lat lon
What do I need to do to get the values of lat and lon? (444 and 555)
If you want to iterate over both keys and values of the dictionary, do this:
for key, value in data.items():
print(key, value)
What error is it giving you?
If you do exactly this:
data = json.loads('{"lat":444, "lon":555}')
Then:
data['lat']
SHOULD NOT give you any error at all.
Using Python to extract a value from the provided Json
Working sample:
import json
import sys
# load the data into an element
data = {"test1": "1", "test2": "2", "test3": "3"}
# dumps the json object into an element
json_str = json.dumps(data)
# load the json to a string
resp = json.loads(json_str)
# print the resp
print(resp)
# extract an element in the response
print(resp['test1'])
json.loads(...). But If I need to load the JSON file as a "myfile.json" with the related commands, it outputs an error.... What should I do??Using your code, this is how I would do it. I know an answer was chosen, just giving additional options.
data = json.loads('{"lat":444, "lon":555}')
ret = ''
for j in data:
ret = ret+" "+data[j]
return ret
When you use "for" in this manner you get the key of the object, not the value, so you can get the value by using the key as an index.
for key, value in data.items(): instead. It is more readable and less error-prone (also more efficient if one would care about that)There's a Py library that has a module that facilitates access to Json-like dictionary key-values as attributes: pyxtension and Github source code
You can use it as:
j = Json('{"lat":444, "lon":555}')
j.lat + ' ' + j.lon
With a JSON string such as '{"lat":444, "lon":555}', json.loads() creates a dictionary, so to get its values, you do so as you would get the values in a dictionary. Iteration over a dictionary is an iteration over its keys (for j in data: is the same as for j in data.keys():); however, to iterate over its values, you need to use .values():
import json
data = json.loads('{"lat":444, "lon":555}')
print(type(data)) # <class 'dict'>
print(data) # {'lat': 444, 'lon': 555}
for j in data.values(): # <--- iterate over values
pass
Note that json.loads converts json arrays into lists. If you need to get a value of a dictionary in a list, then you will need to index the list for the dictionary first to get the value. This is an easy mistake to make especially if an API returns a JSON array with a single object in it. For example:
s = '[{"lat":444, "lon":555}]'
data = json.loads(s) # [{'lat': 444, 'lon': 555}]
data['lat'] # <--- TypeError
data[0]['lat'] # <--- OK
If you want to get values from a JSON document, then open the file first and pass the file handle to json.load() instead. Depending on the document structure, json.load() would return dictionary or list, just like json.loads().
import json
with open('data.json', 'r') as f:
data = json.load(f)
for j in data.values():
pass
' '.join(data)