declaring classes from imported modules in python

Question

In python you have to use

import <module>

to import a file with classes.

Imagine the module contains multiple classes

And now I want to declare an object

x = module.object1Name(parameter1,parmeter2)

How can I declare that object without having to access it through module? (So like this below)

x = object1Name(parameter1,parameter2)

Also I do not want to use the following because it would mean I would have to do that for every class.

from <module> import <objectName>

João Paulo Carvalho · Accepted Answer · 2022-12-24T16:35:10.063

2

You can use the following statement, that will import everything from the module:

from <module> import *

But it is not a good practice, for some reasons:

Your code must import only what you uses.
The zen of python says "explicit is better than implicit", so if you want to use something, you need to import it explicitly.
Improve the readability of your code.

I suggest to use the explicit imports in what you want to use.

from <module> import <object1>, <object2>

Or, like below:

from <module> import (
    <object1>,
    <object2>,
    <object3>,
    <object4>
)

edited Dec 24 '22 at 16:35

answered Dec 23 '22 at 16:20

João Paulo Carvalho

50
1
7

1

Thank you. What does the '*' mean (does it mean all?) – Muffin Dec 23 '22 at 16:22
Also why is it bad practice? Is it because of readability and understanding – Muffin Dec 23 '22 at 16:23
Yes, it means that python will import everything from the module. – João Paulo Carvalho Dec 23 '22 at 16:25
The idea of the bad practice is that your code must import only what you uses. Furthermore, the zen of python says "explicit is better than implicit". If you need to use something more, you need to import it explicitly. This also improve the readability as you said. – João Paulo Carvalho Dec 23 '22 at 16:29
pontual ?= one-off – tehCheat Dec 23 '22 at 16:34
1

With pontual, I want to say explicitly what you want. May be one, two, or more objects from the module. – João Paulo Carvalho Dec 23 '22 at 16:37

tehCheat · Answer 2 · 2022-12-23T16:26:39.100

You can combine multiple from <module> import <objectName> statements with commas and parentheses.

For example:

from <module> import <objectNameA>, <objectNameB>

or

from <module> import (<objectNameA>, <objectNameB>)

The latter will work across multiple lines (ref).

Using import * from <module> (import everything from <module>) is bad because it risks overriding functions, classes, and variables from other modules, and it violates the Zen of Python "better to be explicit" value.

declaring classes from imported modules in python

2 Answers2