Decorators in python

#code #python #datastructure

  • Decorators is being use to decorate functions
  • They execute some process related to decorated function or return decorated function or replace by another function 
>>> def deco(func):
...     def inner():
...         print('running inner()')
...     return inner  (1)
...
>>> @deco
... def target():  (2)
...     print('running target()')
...
>>> target()  (3)
running inner()
>>> target  (4)
<function deco.<locals>.inner at 0x10063b598>
  • They are synthetic sugar
  • They executed in import time or the modules are being imported 

registry = []  # (1)

def register(func):  # (2)
    print(f'running register({func})')  # (3)
    registry.append(func)  # (4)
    return func  # (5)

@register  # (6)
def f1():
    print('running f1()')

@register
def f2():
    print('running f2()')

def f3():  # (7)
    print('running f3()')

def main():  # (8)
    print('running main()')
    print('registry ->', registry)
    f1()
    f2()
    f3()

if __name__ == '__main__':
    main()  # (9)
python3 registration.py
running register(<function f1 at 0x100631bf8>)
running register(<function f2 at 0x100631c80>)
running main()
registry -> [<function f1 at 0x100631bf8>, <function f2 at 0x100631c80>]
running f1()
running f2()
running f3()
  • Usually decorators are implemented in one module and used in another module
  • Usually decorators return and define inner function
  • Using decorators to implement design pattern strategy: Strategy using functions
Eu com algumas figuras que representa análise de dados/ciência
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#code #python #datastructure