I'm looking at some Python code which used the @
symbol, but I have no idea what it does. I also do not know what to search for as searching Python docs or Google does not return relevant results when the @
symbol is included.
Today you learned how the at symbol @ is used in Python. To recap, the main use for the @ symbol is decorators. A decorator is used to extend the functionality of a function, method, or class from outside.
The @ (at) operator is intended to be used for matrix multiplication. No builtin Python types implement this operator. The @ operator was introduced in Python 3.5.
In Python strings, the backslash "\" is a special character, also called the "escape" character. It is used in representing certain whitespace characters: "\t" is a tab, "\n" is a newline, and "\r" is a carriage return.
Dec 14, 2020. The Python += operator lets you add two values together and assign the resultant value to a variable. This operator is often referred to as the addition assignment operator.
Let’s take a more in-depth look at both of these. The main use case of the symbol @ in Python is decorators. In Python, a decorator is a function that extends the functionality of an existing function or class. Here the extend_behavior decorator function extends the behavior of some_func.
If you are referring to some code in a python notebook which is using Numpy library, then @ operator means Matrix Multiplication. For example: Decorators were added in Python to make function and method wrapping (a function that receives a function and returns an enhanced one) easier to read and understand.
@ can be used for matrix multiplication and decorator in python. While this link may answer the question, it is better to include the essential parts of the answer here and provide the link for reference. Link-only answers can become invalid if the linked page changes. - From Review
An @ symbol at the beginning of a line is used for class, function and method decorators. Read more here: The most common Python decorators you'll run into are: If you see an @ in the middle of a line, that's a different thing, matrix multiplication.
An @
symbol at the beginning of a line is used for class, function and method decorators.
Read more here:
PEP 318: Decorators
Python Decorators
The most common Python decorators you'll run into are:
@property
@classmethod
@staticmethod
If you see an @
in the middle of a line, that's a different thing, matrix multiplication. See this answer showing the use of @
as a binary operator.
class Pizza(object): def __init__(self): self.toppings = [] def __call__(self, topping): # When using '@instance_of_pizza' before a function definition # the function gets passed onto 'topping'. self.toppings.append(topping()) def __repr__(self): return str(self.toppings) pizza = Pizza() @pizza def cheese(): return 'cheese' @pizza def sauce(): return 'sauce' print pizza # ['cheese', 'sauce']
This shows that the function
/method
/class
you're defining after a decorator is just basically passed on as an argument
to the function
/method
immediately after the @
sign.
The microframework Flask introduces decorators from the very beginning in the following format:
from flask import Flask app = Flask(__name__) @app.route("/") def hello(): return "Hello World!"
This in turn translates to:
rule = "/" view_func = hello # They go as arguments here in 'flask/app.py' def add_url_rule(self, rule, endpoint=None, view_func=None, **options): pass
Realizing this finally allowed me to feel at peace with Flask.
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