如何将一个Python装饰器应用于一个函数?
可能重复:
了解Python装饰器
您能否给出一个解释装饰器的简短代码示例?
def spam(func):
def wrapped(*args, **kwargs):
print "SPAM"
return func(*args, **kwargs)
return wrapped
@spam #this is the same as doing eggs = spam(eggs)
def eggs():
print "Eggs?"
注意你也可以使用类来编写装饰器
class Spam(object):
def __init__(self, func):
self.func = func
def __repr__(self):
return repr(self.func)
def __call__(self, *args, **kwargs):
print "SPAM"
return self.func(*args, **kwargs)
@Spam
def something():
pass
装饰器接受函数定义并创建一个执行此函数并转换结果的新函数。
@deco
def do():
...
相当于:
do = deco(do)
例:
def deco(func):
def inner(letter):
return func(letter).upper() #upper
return inner # return a function object
#This
@deco
def do(number):
return chr(number) # number to letter
#end
# is equivalent to this
def do2(number):
return chr(number)
do2 = deco(do2)
#end
# 65 <=> 'a'
print(do(65))
print(do2(65))
>>> B
>>> B
为了理解装饰器,重要的是要注意,装饰器创建了一个新的函数do,它是执行func并转换结果的内部函数。
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