Python中的装饰器函数
代码示例
装饰蟒蛇
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装饰器
# decorators are user to decorate functions like what to do before/after calling the function
import time
def delay_decorator(function):
def wrapper_function():
print("-----------------------I am gonna greet you--------------------------")
time.sleep(2)# waits for 2 seconds
function() # calls the function
time.sleep(1)# waits for 1 sec
print("------------------How do you feel about that greet?-------------------")
return wrapper_function
@delay_decorator
def greet():
print("Helllllloooooooooo")
greet()装饰器python
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函数装饰器
#Decorator are just function that take function as first
#parameter and return a function
def logging(f):
def decorator_function(*args, **kwargs):
print('executing '+f.__name__)
return f(*args, **kwargs)
return decorator_function
#Use it like this
@logging
def hello_world():
print('Hello World')
#calling hello_world() prints out:
#executing hello_world
#Hello Worldpython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)
蟒蛇的装饰
from functools import wraps
def debug(func):
@wraps(func)
def out(*args, **kwargs):
print('hello world')
return func(*args, **kwargs)
return out
@debug
def add(x, y):
return x + yPython中函数装饰器的例子
from functools import wraps
def logit(logfile='out.log'):
def logging_decorator(func):
@wraps(func)
def wrapped_function(*args, **kwargs):
log_string = func.__name__ + " was called"
print(log_string)
# Open the logfile and append
with open(logfile, 'a') as opened_file:
# Now we log to the specified logfile
opened_file.write(log_string + '\n')
return func(*args, **kwargs)
return wrapped_function
return logging_decorator
@logit()
def myfunc1():
pass
myfunc1()
# Output: myfunc1 was called
# A file called out.log now exists, with the above string
@logit(logfile='func2.log')
def myfunc2():
pass
myfunc2()
# Output: myfunc2 was called
# A file called func2.log now exists, with the above string
Python中函数装饰器的例子
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
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