How (At Symbol) @ Works In Python

Let's break it down loosy-goosy-style, no holds barred:

So, you slap an "@" in front of a function, like so:

<?php
@print
def hi(): pass

@print
def hi(): pass

Then you run it, and bam! It spits out ``. But hold up, you didn't see no `print()` in there? Don't sweat it, here's the lowdown:

<?php
@print()
def hi(): pass

@print()
def hi(): pass

It's just like:

<?php
def hi(): pass

hi = print(hi)

def hi(): pass

hi = print(hi)

Because of that "@" symbol, our little `print(hi)` party gets started – that's why our `hi()` function is getting cozy with the screen.

Now, let's talk shop – Decorator VS Decoratee:

<?php
@something
def hello():
  # do stuff

@something
def hello():
# do stuff

Here, something's the big shot decorator function, and hello's the one getting dolled up – the decoratee function.

And how does it go down? Like this:

<?php
hello = something(hello)

hello = something(hello)

Our decorator something's like, "Hey there, hello, let me jazz you up a bit," and voila!

Now, a less pointless example:

<?php
def hi(name):
  return 'hello ' + name

def hi(name):
return 'hello ' + name

Say you wanna spice up `hi(name)` without messin' with its insides. Time to play decorator!

<?php
def add_exclamation(function):
  def wrapper(name):
    return function(name) + '!'
  return wrapper

@add_exclamation
def hi(name):
  return 'hello ' + name

def add_exclamation(function):
  def wrapper(name):
    return function(name) + '!'
  return wrapper

@add_exclamation
def hi(name):
  return 'hello ' + name

Boom! We just gave `hi(name)` a makeover without touchin' its code.

<?php
print(hi('tom'))

# hello tom!

print(hi('tom'))

# hello tom!

See that extra exclamation? That's the work of our decorator – add_exclamation.

In summary, the "@" symbol is primarily used as a decorator syntax in function definitions, allowing functions to modify or extend the behavior of other functions or methods. When placed before a function definition, it indicates that the following function will be used as a decorator, which means it will wrap around or modify the behavior of the function immediately below it. Decorators are commonly employed for tasks such as logging, authorization, caching, and more, providing a concise and elegant way to enhance the functionality of functions without modifying their core code. Additionally, the "@" symbol is also used in matrix multiplication operations introduced in Python 3.5, where it serves as a concise and intuitive operator for performing matrix multiplications between two arrays or matrices using the `numpy` library.

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