Rodrigo πŸπŸš€ Profile picture
Sep 23, 2021 β€’ 14 tweets β€’ 5 min read β€’ Read on X
Do you know what the Python 🐍 `type` is?

But do you _really_ know what it is?

Here is a valuable thread that will give you insights into what `type` is and does.

Let's go πŸ‘‡πŸ§΅
What does `type` do?

You might say that `type` takes an object and returns the type of the argument.

Here are some examples:
Fine, so `type` is a function!

Or is it..?

Take a look at the example above.

`sum` is a built-in function and `type(sum)` returned β€œbuilt-in function or method”.

So, logically, if `type` is a (built-in) function, the type of `type` should give the same thing:
But it said that the type of `type` is... `type`? 🀯

How's that?

What does that even mean?

Well, let's take a step back and look at `str` and `int`:
Interesting!

So `int` and `str` are built-in functions that convert things to integers and strings, respectively.

Right?

Well, let's check their type!

As it turns out, the type of `int` and `str` are also... `type`!
Ok, so these things seem to be connected!

Let's take one more step back.

Let's look at what the type of `3` is and to what `int` is:
Hey, `type(3)` and `int` look like the same thing!

Heck, they _are_ the same thing:
So `type(3)` and `int` are the same thing!

That's interesting!

So, `int` is not a function, and it builds integers, so `int` is like an integer factory!

That's why `int` shows like β€œclass int”, because it is a class.

This applies to `int`, `str`, `list`, `tuple`, `dict`, ...
So, all these objects are the objects that represent the classes.

All these objects are factories of a specific kind.

`str` is a string factory.

`dict` is a dictionary factory.

Your own custom classes, are also factories:
But that brings us close to the end!

There's a bunch of objects, that we use regularly, that are just factories.

Fine, fine.

So, if all these objects are factories, maybe that's their type!

Their type could be β€œfactory”!
If something has the type β€œtype”, it means it's a factory.

Ok, so checking the type of `type` again shows that the type of `type` is... `type`.

So `type` is also a factory!

So what does `type` produce?

Let's see:
So `type` is producing other factories...

Meaning `type` is a factory of factories! 🀯🀯🀯

I mean, you can even create new classes dynamically with `type`! (Not that you generally should...)

Here's the `Person` class from before:
And that's it, for now!

Recap:

πŸ‘‰Β `int`, `str`, `list`, ..., are NOT functions, but classes. Akin to the ones you create with the `class` keyword.

πŸ‘‰ These are like β€œfactories” of objects.

πŸ‘‰ `type` accepts objects and returns classes, so `type` is a factory of factories!
I hope you found value in this tweet!

If you did, follow me (@mathsppblog) for more content like this!

There's plenty of amazing Python 🐍 content in store!

Also, consider retweeting the first tweet of this thread if you learnt something new 😊

β€’ β€’ β€’

Missing some Tweet in this thread? You can try to force a refresh
γ€€

Keep Current with Rodrigo πŸπŸš€

Rodrigo πŸπŸš€ Profile picture

Stay in touch and get notified when new unrolls are available from this author!

Read all threads

This Thread may be Removed Anytime!

PDF

Twitter may remove this content at anytime! Save it as PDF for later use!

Try unrolling a thread yourself!

how to unroll video
  1. Follow @ThreadReaderApp to mention us!

  2. From a Twitter thread mention us with a keyword "unroll"
@threadreaderapp unroll

Practice here first or read more on our help page!

More from @mathsppblog

May 9
Hide private information in your Python code.

Suppose you want to print an email...

But you want to create that cool ro*****@mathspp.com effect.

This is pretty easy to achieve in Python!

All you need to do is use an f-string and use the appropriate format specifiers. Diagram showing how you can use f-strings and their format specification to redact private or sensitive information, like email addresses.  The code from the diagram:  def redact_email(email):     user, _, domain = email.partition("@")     return f"{user[:2]:*<{len(user)}}@{domain}"  print(redact_email("rodrigo@mathspp.com")) # ro*****@mathspp.com
πŸ‘‰ the first thing you do is use `str.partition` to grab the email β€œuser” and the domain.

We will redact only the user (but you could also redact the domain with the same process).

The `user[:2]` shows the first two characters.

That's the β€œro”.

But how do you get β€œro*****”?
πŸ‘‰ use an f-string and the width specifier.

You want to create a field as wide as β€œrodrigo”:

r o _ _ _ _ _

The length of this field is `len(user)`, so you use `{len(user)}` INSIDE the format spec.

This creates a field with the correct width.
Read 6 tweets
May 18, 2023
I know `print` is the first Python 🐍 function you learned! πŸš€

And yet, you don't know this about `print` πŸ‘‡ Image
What you know for sure is that `print` will take an object and it will print it on the screen.

That's the basic functionality it provides: Image
Maybe you don't know that `print` can actually print multiple things!

If you pass multiple arguments, they all get printed: Image
Read 11 tweets
May 17, 2023
I'll tell you the story of a person that had the wrong name…

And how to prevent that in Python 🐍 with properties πŸš€.

πŸ‘‡ Image
John Doe was a regular guy and when he was born, he was inserted into the government's database of people.

They created a new `Person` and added John's details: Image
John never liked his name Doe, though.

So Joe decided to change his name to Smith.

And so he did.

He updated his last name, but the government `Person` STILL had the wrong name! Image
Read 10 tweets
May 14, 2023
Opening a file to read/write is a common task in Python 🐍.

Here is how to do it right! πŸš€

πŸ‘‡ Image
Python has a built-in `open` that takes a file path and opens that file.

Then, you have to specify whether you want to open the file to read, write, or append.

But this isn't half of the story! Image
The default behaviour is to open the file to read/write text.

This works well with TXT or CSV files, for instance.

If you need to open a file to read its binary contents, you can add a `"b"` to the mode: Image
Read 6 tweets
May 13, 2023
The Python 🐍 built-in `round` is great. πŸš€

Here are some tips on it. πŸ‘‡ Image
The purpose of `round` is to… round numbers!

It rounds numbers to the closest integer.

These are some simple examples: Image
However, if the number ends in `.5`, what is the closest integer?

In that case, `round` will choose the even number.

This means it may round up or down πŸ€ͺ

(In school, I was taught to round `.5` up… 🀷) Image
Read 6 tweets
May 12, 2023
Error handling in Python 🐍 made simple. πŸš€

πŸ‘‡ Image
The keyword `try` is used before code that might fail.

So, if you know something can raise an error, you can write it inside a `try` statement: Image
Now that the code is inside a `try` statement, you need to tell Python what error you want to handle, and how.

That's when the keyword `except` comes in! Image
Read 7 tweets

Did Thread Reader help you today?

Support us! We are indie developers!


This site is made by just two indie developers on a laptop doing marketing, support and development! Read more about the story.

Become a Premium Member ($3/month or $30/year) and get exclusive features!

Become Premium

Don't want to be a Premium member but still want to support us?

Make a small donation by buying us coffee ($5) or help with server cost ($10)

Donate via Paypal

Or Donate anonymously using crypto!

Ethereum

0xfe58350B80634f60Fa6Dc149a72b4DFbc17D341E copy

Bitcoin

3ATGMxNzCUFzxpMCHL5sWSt4DVtS8UqXpi copy

Thank you for your support!

Follow Us!

:(