What Does the "At" (@) Symbol Do in Python

What does the at (@) symbol do in Python?

An @ symbol at the beginning of a line is used for class and function decorators:

• PEP 318: Decorators
• Python Decorators

The most common Python decorators are:

• @property
• @classmethod
• @staticmethod

An @ in the middle of a line is probably matrix multiplication:

• @ as a binary operator.

What is the '@=' symbol for in Python?

From the documentation:

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. @= is matrix multiplication followed by assignment, as you would expect. They map to __matmul__, __rmatmul__ or __imatmul__ similar to how + and += map to __add__, __radd__ or __iadd__.

The operator and the rationale behind it are discussed in detail in PEP 465.

What does @z mean in Python

@ refers to the matrix multiplication operator.

From the numpy docs:

The @ operator can be used as a shorthand for np.matmul on ndarrays.

x1 = np.array([2j, 3j])
x2 = np.array([2j, 3j])
x1 @ x2
(-13+0j)

Use of @ in Python

The @ character denotes a decorator. Decorators are functions that can modify or extend behavior of another function temporarily by wrapping around them.

Decorators wrap around a function by receiving them as a parameter. The @ syntax (also known as "pie" syntax) applies the classmethod decorator to cmeth after it is defined in your snippet.

You can read more about the specific decorator from your example (classmethod) here.

What is the Meaning Of '@' before A function In Python 3?

It represent the Decorator. A decorator is a function that takes another function and extends the behavior of the latter function without explicitly modifying it.

def decorator_function(func):
    def inner_function():
        print("Before the function is called.")
        func()
        print("After the function is called.")
    return inner_function

@decorator_function
def args_funtion():
    print("In the middle we are!")

Actually this @decorator_function decorator perform the same job as

args_funtion = decorator_function(args_funtion)
args_funtion()

@ operator at the beginning of the line in python

I think what you are looking for is called PythonDecorators

Here is the Wiki For Python Decorators

A Python decorator is a specific change to the Python syntax that allows us to more conveniently alter functions and methods (and possibly classes in a future version). This supports more readable applications of the DecoratorPattern but also other uses as well.

The best way to understand them is from Corey Schafer's Video on Python Decorators

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