可帶引數的裝飾器

Python 函式寫作

Shayne Miel

Software Architect @ Duo Security

def run_three_times(func):
  def wrapper(*args, **kwargs):
    for i in range(3):
      func(*args, **kwargs)
  return wrapper

@run_three_times
def print_sum(a, b):
  print(a + b)

print_sum(3, 5)

8
8
8

run_n_times()

def run_n_times(func):
  def wrapper(*args, **kwargs):
    # 我們要如何把「n」傳進這個函式？
    for i in range(???):
      func(*args, **kwargs)
  return wrapper

@run_n_times(3)
def print_sum(a, b):
  print(a + b)

@run_n_times(5)
def print_hello():
  print('Hello!')

裝飾器工廠

def run_n_times(n):
  """定義並回傳一個裝飾器"""

  def decorator(func):

    def wrapper(*args, **kwargs):

      for i in range(n):
        func(*args, **kwargs)

    return wrapper

  return decorator

@run_n_times(3)
def print_sum(a, b):
  print(a + b)

def run_n_times(n):
  """定義並回傳一個裝飾器"""
  def decorator(func):
    def wrapper(*args, **kwargs):
      for i in range(n):
        func(*args, **kwargs)
    return wrapper
  return decorator

run_three_times = run_n_times(3)

@run_three_times
def print_sum(a, b):
  print(a + b)

@run_n_times(3)
def print_sum(a, b):
  print(a + b)

使用 run_n_times()

@run_n_times(3)
def print_sum(a, b):
  print(a + b)

print_sum(3, 5)

8
8
8

@run_n_times(5)
def print_hello():
  print('Hello!')

print_hello()

Hello!
Hello!
Hello!
Hello!
Hello!

一起來練習吧！

Python 函式寫作