Python: making make_class TypeError: object does not support item assignment

Question

I have this problem while making my simple make_class. Here is my code:

def make_class(attrs, class_name, base=None):
    def get(name):
        if name in attrs:
            return attrs[name]
        elif base:
            return base['get'](name)

    def set(name, value):
        attrs[name] = value

    return cls

Running the program -

def make_user():
    return make_class('Test', {'code': 0.202})


def make_user_class():
    def init(self, owner):
        self['set']('name', owner)
        self['set']('number1', 0)

    return make_class(Test, 'TUser', {'__init__': init, 'code': 0.03})


Test = make_user()
TAccount = make_user_class()
Test['get']('name')

I tried to set the value in the def set(name, value): function but then it says

Traceback (most recent call last): File "main.py", line 276, in Test = make_user() File "main.py", line 265, in make_user return make_class('TAccount', {'interest': 0.202}) File "main.py", line 259, in make_class cls['set']('class_name', class_name) File "main.py", line 232, in set attrs[name] = value TypeError: 'str' object does not support item assignment

Your code is indented incorrectly. Please edit your question. Also see minimal reproducible example. — DapperDuck
can you make a minimal reproducible example of your error? also, post the whole error message — oskros
@oskros Indeed, I just don't want to edit the question, if that is what the mistake is. — DapperDuck
Also, please edit your question to provide the full error traceback, the current output, and the expected output. — DapperDuck

chepner chepner · Accepted Answer · 2021-01-05T13:00:14

Here is the signature you used to define make_class:

def make_class(attrs, class_name, base=None):

When you call make_class, the positional arguments need to be in the correct order:

def make_user():
    return make_class({'code': 0.202}, 'Test')


def make_user_class():
    def init(self, owner):
        self['set']('name', owner)
        self['set']('number1', 0)

    return make_class({'__init__': init, 'code': 0.03}, 'TUser', Test)

Note that having make_user_class refer to a predefined global Test probably isn't a great idea. make_user_class itself should probably take the desired base class as an argument itself:

def make_user_class(base):
    def init(self, owner):
        self['set']('name', owner)
        self['set']('number1', 0)

    return make_class({'__init__': init, 'code': 0.03}, 'TUser', base)


Test = make_user()
TAccount = make_user_class(Test)
Test['get']('name')

Python: making make_class TypeError: object does not support item assignment

1 Answers