CODEWITHSUNDEEP
pythonpython-3.xpostgresqlpython-2.7
Raghav Patnecha
Raghav Patnecha

Reputation: 736

Convert a dictionary of type str to float Python

There is something strange going on when I try to query PostgreSQL database and retrieve values of only one column and then converting it to JSON:

latitude = Places.query.with_entities(Places.latitude).all()
longitude = Places.query.with_entities(Places.longitude).all()
user_schema = UserSchema(many=True, strict = True)
print user_schema
output = user_schema.dump(latitude).data

output = json.dumps([dict(r) for r in output], default=alchemyencoder)
print output         #[{"latitude": 28.6333}, {"latitude": 28.6333},...]
print type(output)   #<type 'str'>

Although it seems that the result of output is a list of dictionaries and can be iterated to do operations but then in the process of iterating over this dict I was getting errors:

TypeError: string indices must be integers, not str

So, I check the type(output) and it gives me str which is why?

Also, When I try to convert it to a float or int using 

output = float(output)

I get an error:

ValueError: could not convert string to float: [{"latitude": 28.6333}, {"latitude": 28.6333},....]

Upvotes: 1

Views: 194

Answers (1)

Stephen Rauch
Stephen Rauch

Reputation: 49862

If you do not want a string, you should not be using json.dumps() . How about:

Code:

[x["latitude"] for x in output]

Test Code:

latitude = Places.query.with_entities(Places.latitude).all()
longitude = Places.query.with_entities(Places.longitude).all()
user_schema = UserSchema(many=True, strict = True)
print user_schema
output = user_schema.dump(latitude).data

print([x["latitude"] for x in output])

Upvotes: 1

Related Questions