Iterating over a dictionary and creating an object for each key with its values within the same object

Question

import random
import os
import json

class User:
    def _init_(self, username, password, balance):
        self.username = username
        self.password = password
        self.balance = balance



def file_read(source):
    with open (source) as file:
        data = file.read()
        dictionary = json.loads(data)
        return dictionary

and then the external file is this

{"John":["pass123", 2000], "Jenson": ["pass123", 2000]}

my initial thought was to use a for items in dict but i am unsure how to create multiple objects from that preferably being named by username thank you.

what is the output you need for the current input file that you've shown above? — Yatish Kadam, Dec 04 '19 at 19:50
it will return the dictionary stored in the external file and store it within that variable — J.Rimmer, Dec 04 '19 at 19:53

felipe · Answer 1 · 2019-12-04T20:03:07.890

Probably what you are looking for. Remember it is __init__ and not _init_.

import json

def file_read(source):
    with open(source) as file:
        data = file.read()
        dictionary = json.loads(data)
        return dictionary

class User:
    def __init__(self, username, password, balance):
        self.username = username
        self.password = password
        self.balance = balance

    def __str__(self): # String representation of the object for the output.
        return f"{self.username}@{self.password} with balance of {self.balance}"

dictionary = file_read("file.json")

users = []
for key, item in dictionary.items():
    user = User(key, item[0], item[1])
    users.append(user)

# Printing results for output sake.
for user in users:
    print(user)

outputs:

John@pass123 with balance of 2000
Jenson@pass123 with balance of 2000

with file.json as:

{"John":["pass123", 2000], "Jenson": ["pass123", 2000]}

sorry im just starting out with oop i shall have at the look at the code you have sent and try and implement this thankyou — J.Rimmer, Dec 04 '19 at 20:04
No need to be sorry -- we all started somewhere. The second to last `for-loop` is where we are iterating through the items of the dictionary through the use of [`dictionary.items()`](https://docs.python.org/3/tutorial/datastructures.html#looping-techniques), and on the line `user = User(key, item[0], item[1])` we are creating our user object. — felipe, Dec 04 '19 at 20:49

score 1 · Answer 2 · answered Dec 04 '19 at 19:59

1

Simple solution using a dict comprehension and var-args:

{ k: User(k, *v) for k, v in file_read(filename).items() }

Alternatively you can do it with destructuring:

{ k: User(k, pw, bal) for k, (pw, bal) in file_read(filename).items() }

answered Dec 04 '19 at 19:59

kaya3

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Yatish Kadam · Answer 3 · 2019-12-04T20:01:44.923

0

What i think you are asking is to create objects for each of the names in the file.

class User:
    def __init__(self, username, password, balance):
        self.username = username
        self.password = password
        self.balance = balance
def file_read(source):
    with open (source) as file:
       data = file.read()
       dictionary = json.loads(data)
       return dictionary
dicValuesRead = file_read(source)
d = {}
for k,v in dicValuesRead.items():
    d[k] = User(k, v[0], v[1])

print (d)

edited Dec 04 '19 at 20:01

answered Dec 04 '19 at 19:59

Yatish Kadam

454
2
11

`file_read` needs to be outside the `class User` for it be callable. – felipe Dec 04 '19 at 20:00
1

ah yes editing code on this is hard.. ill fix it thanks – Yatish Kadam Dec 04 '19 at 20:01
thank you i shall have a look at dictionary comprehensions – J.Rimmer Dec 04 '19 at 20:03
yes the comprehension is cleaner solution to this.. I like @kaya3 answer below.. Also not as Felipe mentioned youll need to use __init__ in your code.. – Yatish Kadam Dec 04 '19 at 20:05

wwii · Answer 4 · 2019-12-04T20:38:30.263

preferably being named by username

That is problematic, the most common solution for that part of your question is to create a dictionary of {username:object} pairs. See How do I create a variable number of variables?

Your function returns a dictionary.

iterate over the dictionary items which will produce (name,(password,balance)) tuples
for each item extract the individual values; name,(password,balance)= item
pass those to the class to make a new object and add it to the dictionary
new_dict[name] = object

Iterating over a dictionary and creating an object for each key with its values within the same object

4 Answers4