Make Dot Notation More Powerful with Getters and Setters

The elegance of dot notation combined with the power of getters and setters.

Avi Chawla

Feb 20, 2024

Dot notation provides a concise and elegant way to access and modify an object’s attributes.

Yet, with dot notation, we can not validate the updates made to an attribute.

This means we can assign invalid values to an instance’s attributes, as shown below:

One common way to avoid this is by defining a setter (set_side()), which validates the assignment step.

But explicitly invoking a setter method isn’t as elegant as dot notation, is it?

Ideally, we would want to:

Use dot notation
and still apply those validation checks

The @𝐩𝐫𝐨𝐩𝐞𝐫𝐭𝐲 decorator in Python can help.

Here’s how we can use it here.

First, define a getter as follows:

Declare a method with the attribute’s name.
There’s no need to specify any parameters for this method.
Decorate it with the @𝐩𝐫𝐨𝐩𝐞𝐫𝐭𝐲 decorator.

Next, define a setter as follows:

Declare a method with the attribute’s name.
Specify the parameter you want to update the attribute with.
Write the conditions as you usually would in any other setter method.
Decorate it with the @𝐚𝐭𝐭𝐫𝐢𝐛𝐮𝐭𝐞-𝐧𝐚𝐦𝐞.𝐬𝐞𝐭𝐭𝐞𝐫 decorator.

Done!

Now, you can use the dot notation while still having validation checks in place.

This is demonstrated below:

This approach offers both:

The validation and control of explicit setters and getters.
The elegance of dot notations.

Isn’t that cool?

Here are some interesting reads around Python OOP, which we have covered in the past and you must read next:

Also, here’s a full deep dive into Python OOP if you want to learn more about advanced OOP in Python: Object-Oriented Programming with Python for Data Scientists.

👉 What are some cool things you know about Python OOP?

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