Python中的装饰器

def our_decorator(func):
    def function_wrapper(x):
        print("Before calling " + func.__name__)
        func(x)
        print("After calling " + func.__name__)
    return function_wrapper

@our_decorator
def foo(x):
    print("Hi, foo has been called with " + str(x))

foo("Hi")

python中的装饰器

'pass function which we want to decorate in decorator callable object'
def our_decorator(func):  # func is function to be decorated by decorator
  
  def wrapper(x):       # x is parameter which is passed in func
    if x%2==0:
      return func(x)
    else:
      raise Exception("number should be even")
  return wrapper

@ our_decorator
def func(x):         # actual function 
  print(x,"is even")
func(2)
func(1)

' if you do not want to use @'
func=our_decorator(func)
func(2)


  
  

from functools import wraps

def logit(func):
    @wraps(func)
    def with_logging(*args, **kwargs):
        print(func.__name__ + " was called")
        return func(*args, **kwargs)
    return with_logging

@logit
def addition_func(x):
   """Do some math."""
   return x + x


result = addition_func(4)
# Output: addition_func was called

python中的装饰器

# this functon converts any string into uppercase
def deco(function):
    def wrap(s):
        return s.upper()
        function(s)
    return wrap

@deco
def display(s):
    return s 
print(display("not bad"))

def first(msg):
    print(msg)


first("Hello")

second = first
second("Hello")

python中的装饰器

def deco(func):
    def wrap(s):
        d = {}
        for i in s:
            d[i] = s.count(i)
        func(s)
        return d
    return wrap

@deco
def count(stng):
    return stng
mystring = "scorpio"  
print(count(mystring))