Dekoratorer

Att skriva funktioner i Python

Shayne Miel

Software Architect @ Duo Security

Funktioner

funktion

Dekoratorer

funktion med dekorator

Ändra indata

ändra indata

Ändra utdata

ändra utdata

Ändra funktion

ändra funktion

Hur ser en dekorator ut?

@double_args
def multiply(a, b):
  return a * b

multiply(1, 5)

Dekoratorn double_args

def multiply(a, b):
  return a * b

def double_args(func):
  return func

new_multiply = double_args(multiply)

new_multiply(1, 5)

multiply(1, 5)

Dekoratorn double_args

def multiply(a, b):
  return a * b

def double_args(func):

  # Define a new function that we can modify
  def wrapper(a, b):

    # For now, just call the unmodified function
    return func(a, b)

  # Return the new function
  return wrapper

new_multiply = double_args(multiply)

new_multiply(1, 5)

Dekoratorn double_args

def multiply(a, b):
  return a * b

def double_args(func):
  def wrapper(a, b):

    # Call the passed in function, but double each argument
    return func(a * 2, b * 2)

  return wrapper

new_multiply = double_args(multiply)

new_multiply(1, 5)

Dekoratorn double_args

def multiply(a, b):
  return a * b

def double_args(func):
  def wrapper(a, b):
    return func(a * 2, b * 2)
  return wrapper

multiply = double_args(multiply)

multiply(1, 5)

multiply.__closure__[0].cell_contents

<function multiply at 0x7f0060c9e620>

Dekoratorsyntax

def double_args(func):
  def wrapper(a, b):
    return func(a * 2, b * 2)
  return wrapper



def multiply(a, b):
  return a * b

multiply = double_args(multiply)

multiply(1, 5)

def double_args(func):
  def wrapper(a, b):
    return func(a * 2, b * 2)
  return wrapper


@double_args
def multiply(a, b):
  return a * b



multiply(1, 5)

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Att skriva funktioner i Python