How to create object attributes from dictionary key/values?

Question

I have an excel file that contains some required parameters and their values and I am trying to feed them into the __init__ function of my class entity. I know the below must be setting self.key to each value in turn, but should I be "masking"(?) the .key?:

class Customer:
    def __init__(self):
        for key, value in zip(excelDF.attribs, excelDF.values):
            if key!=None and value !=None:
                self.key= value

To give an example of what I am trying for:

excelDF.attribs=['name','telephone']
excelDF.values=['Tom','01234-567890']
customer1=Customer()
print(customer1.name)
print(customer1.telephone)

gives...

Tom
01234-567890

Use [`setattr()`](https://docs.python.org/2/library/functions.html#setattr) — Leon, May 30 '17 at 10:50
@deepspace answer below is great, small remark for this code: don't use `=` and `!=` for singleton objects like `None`, use `is` if you need such check for some reason — Slam, May 30 '17 at 10:54

DeepSpace · Accepted Answer · 2017-05-30T11:16:50.647

You should be using setattr:

class Customer:
    def __init__(self):
        for key, value in zip(excelDF.attribs, excelDF.values):
            if key is not None and value is not None:
                setattr(self, key, value)

If a key happens to be an invalid Python identifier it will only be accessible with getattr.

Usage example:

keys = ['a', 'b', 'c']
values = [1, 2, 3]

class Customer:
    def __init__(self):
        for key, value in zip(keys, values):
            if key is not None and value is not None:
                setattr(self, key, value)

cust = Customer()
print(cust.a, cust.b, cust.c)
# 1 2 3

score 1 · Answer 2 · answered May 30 '17 at 11:08

1

Another less conventional approach using type to define the class:

Customer = type("Customer",
                (),
                dict(zip(excelDF.attribs, excelDF.values)))

ref: http://python-course.eu/python3_classes_and_type.php

answered May 30 '17 at 11:08

John 9631

527
5
13

1

Correct, but this will get very messy if OP wants to define some methods in `Customer` class. – DeepSpace May 30 '17 at 11:13

score 0 · Answer 3 · answered May 30 '17 at 11:31

I want to present 2 alternatives:

#!/usr/bin/env python3


class Customer:
    def __init__(self, **kwargs):
        self.name = kwargs.get("name")
        self.number = kwargs.get("number")


class Customer2:
    name = ""
    number = ""

    @classmethod
    def from_dict(cls, d):
        o = cls()
        for k in [k for k in vars(cls) if not k.startswith("_")]:
            setattr(o, k, d.get(k))
        return o


keys = ["name", "number", "bla"]
values = ["John", "00109563221", "Blub"]

data = {k: v for k, v in zip(keys, values)}
c1 = Customer(**data)
c2 = Customer2.from_dict(data)

print(c1.name)
print(c2.number)

Here the stress lies on the constructor pulling in what it needs of the data instead of taking all that comes along.

Cave: Solution2 relies on the fact, that you only want dumb data objects, where the only fields you are interested in are defined class variables.

How to create object attributes from dictionary key/values?

3 Answers3