Python: Trying to create a json object with dict (TypeError: cannot unpack non-iterable User object)

Question

I'm trying to make a full JSON object return from the module, which gets all users from database and enters their data in one JSON object, but I get TypeError: cannot unpack non-iterable User object, I don't really know what's the problem.

from application.models import User


class users_eng:

    def __init__(self):
        pass

    def get_users(self):
        users = User.query.all()

        # users output - [<User 9nematix>, <User 3nematix>, <User 6nematix>]

        for user in users:
            users_data = {
                dict(
                    username=user.username,
                    bio=user.profile_bio,
                    role=user.role,
                    profile_picture=user.profile_picture
                ) for user.username, user.profile_bio, user.role, user.profile_picture, *_ in users
            }

        x = json.dumps(users_data)
        print(x)

        return x

_users_ = users_eng()

** EDIT: I updated my code with the other solution in comments, but now I get [<generator object users_eng.get_users.<locals>.<genexpr> at 0x000001AF38C828C8>]

from application.models import User
from flask import session
import json


class users_eng:

    def __init__(self):
        pass

    def get_users(self):
        users = [
            User.query.all()
        ]

        # users output - [<User 9nematix>, <User 3nematix>, <User 6nematix>]
        users_data = []
        for user in users:
            users_data.append(
                dict(
                    username=user.username,
                    bio=user.profile_bio,
                    role=user.role,
                    profile_picture=user.profile_picture,
                ) for user in users
            )

        print(users_data)

        return users_data

_users_ = users_eng()

Nikolaus Gullotta · Accepted Answer · 2020-04-17 19:20:19Z

1

Your user object is not an iterable type. Typically, database models are not. You need to change for user.username user.bio ... to just for user

Additionally dicts are unhashable, so you will encounter another error after fixing the first. I would recommend making your users_data an array of dicts, instead of a dict

Example:

# Ignore this, substitute with your own model
from database.models import User

users = [
    User(email="[email protected]", first="Foo", last="Bar")
]

users_data = [
    dict(
        email=user.email,
        name=f"{user.first} {user.last}",
    ) for user in users
]

An additional example converting this back to a valid JSON object

from json import dumps

from database.models import User

users = [
    User(email="[email protected]", first="Foo", last="Bar")
]

users_data = [
    dict(
        email=user.email,
        name=f"{user.first} {user.last}",
    ) for user in users
]

# This is valid JSON
rv = dumps({"users": users_data})
print(rv)

Output:

{"users": [{"email": "[email protected]", "name": "Foo Bar"}]}

edited Apr 17, 2020 at 19:20

answered Apr 17, 2020 at 18:44

Nikolaus Gullotta

1215 bronze badges

Sign up to request clarification or add additional context in comments.

9 Comments

DzITC Over a year ago

Thanks, but I receive not JSON format - [<generator object users_eng.get_users.<locals>.<genexpr> at 0x000001AF38C828C8>]

Nikolaus Gullotta Over a year ago

Yeah, apologies, I made a mistake in the code and edited it accordingly. Try the new edited version.

DzITC Over a year ago

AttributeError: 'list' object has no attribute 'username'

DzITC Over a year ago

it should be - users = User.query.all()

DzITC Over a year ago

Thanks man, maybe you know any fast solution to remove [] in the JSON?

|

Collectives™ on Stack Overflow

Python: Trying to create a json object with dict (TypeError: cannot unpack non-iterable User object)

1 Answer 1

9 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

9 Comments

Your Answer

Sign up or log in

Post as a guest

Related