python decorator is a crucial(vital,signifiant) process.
decorator mail two category
1:principal function no arguments(parameters):
for example:
principal function:
decorator:
import time
def logger(flag):
def decorator():
def inner():
stat_time=time.time()
func()
end_time=time_time()
print(end_time-start_time）
if flag='true':
print('date is ')
return inner
return decorator
@logger('true')
def test():
print('hello world')
2:principal fuction have arguments:
def logger(flag):
def decorator():
def inner(n):
stat_time=time.time()
func(n)
end_time=time_time()
print(end_time-start_time）
if flag='true':
print('date is ')
return inner
return decorator
from functools import reduce
@logger('true')
def factorial_array(n):
number=reduce(lambda x,y:x*y,range(1,n+1))
print(number)
factorial_array(100)
3:principal fuction have incert arguments:
def logger(flag):
def decorator():
def inner( *args,**kwargs):
stat_time=time.time()
func(*args,**kwargs)
end_time=time_time()
print(end_time-start_time）
if flag='true':
print('date is ')
return inner
return decorator
def add(*args):
number=0
for i in args:
number+=i
print(number)
add(1,2,3,4)
decorator integrated ,function domain,higher-order function ,closure operation.