Type Annotations - Deepstash
Machine Learning With Google

Learn more about computerscience with this collection

Understanding machine learning models

Improving data analysis and decision-making

How Google uses logic in machine learning

Machine Learning With Google

Discover 95 similar ideas in

It takes just

14 mins to read

Type Annotations

Type Annotations

PEP 484 introduced type hints (typing module), a.k.a type annotations. While its main focus was function annotations, it also introduced the notion of type comments to annotate variables.

Ex: primes = [] #type: List[int]

Although type comments work well enough, there are some downsides:

  • text editors highlight comments differently
  • one can’t annotate uninitialized variables
  • mixing type comments with normal ones is confusing

The solution: Variable Annotations


41 reads


Class and Instance Variable Annotations

Class and Instance Variable Annotations

Type annotations can also be used to annotate class and instance variables in class bodies and methods.

In particular, the value-less notation: a: int allows one to annotate instance variables that should be initialized in __init__ or __new__. See the syntax in the picture.



17 reads

Class Variables vs. Instance Variables

Class Variables vs. Instance Variables

When one defines a member variable in the class body definition, the interpreter considers it a class variable.

class Dog:

name: str = ‘Doggo’ # class variable

In the __init__ constructor, one does have access at the ‘name’ class variable using ‘self’. But...


19 reads

Variable Annotations

Variable Annotations

PEP 526 introduced the syntax for Variable Annotations:

var: annotation = value

Variable Annotations don’t affect the Python principle of being a dynamically typed language.

Type annotations can’t create errors, they are checked only by third party type checkers...


26 reads




Backend @deepstash

As I strive to become a better python programmer, I’ve started using type hints and created this intro guide


Explore the World’s

Best Ideas

200,000+ ideas on pretty much any topic. Created by the smartest people around & well-organized so you can explore at will.

An Idea for Everything

Explore the biggest library of insights. And we've infused it with powerful filtering tools so you can easily find what you need.

Knowledge Library

Powerful Saving & Organizational Tools

Save ideas for later reading, for personalized stashes, or for remembering it later.

# Personal Growth

Take Your Ideas


Organize your ideas & listen on the go. And with Pro, there are no limits.

Listen on the go

Just press play and we take care of the words.

Never worry about spotty connections

No Internet access? No problem. Within the mobile app, all your ideas are available, even when offline.

Get Organized with Stashes

Ideas for your next work project? Quotes that inspire you? Put them in the right place so you never lose them.


2 Million Stashers


5,740 Reviews

App Store


72,690 Reviews

Google Play


Don’t look further if you love learning new things. A refreshing concept that provides quick ideas for busy thought leaders.

Shankul Varada

Best app ever! You heard it right. This app has helped me get back on my quest to get things done while equipping myself with knowledge everyday.

Ashley Anthony

This app is LOADED with RELEVANT, HELPFUL, AND EDUCATIONAL material. It is creatively intellectual, yet minimal enough to not overstimulate and create a learning block. I am exceptionally impressed with this app!

Sean Green

Great interesting short snippets of informative articles. Highly recommended to anyone who loves information and lacks patience.

Ghazala Begum

Even five minutes a day will improve your thinking. I've come across new ideas and learnt to improve existing ways to become more motivated, confident and happier.

Giovanna Scalzone

Brilliant. It feels fresh and encouraging. So many interesting pieces of information that are just enough to absorb and apply. So happy I found this.

Laetitia Berton

I have only been using it for a few days now, but I have found answers to questions I had never consciously formulated, or to problems I face everyday at work or at home. I wish I had found this earlier, highly recommended!

Jamyson Haug

Great for quick bits of information and interesting ideas around whatever topics you are interested in. Visually, it looks great as well.

Read & Learn

20x Faster





Access to 200,000+ ideas

Access to the mobile app

Unlimited idea saving & library

Unlimited history

Unlimited listening to ideas

Downloading & offline access

Personalized recommendations

Supercharge your mind with one idea per day

Enter your email and spend 1 minute every day to learn something new.


I agree to receive email updates