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Instance inheritance trial
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class Agro: | |
def __init__(self, parent, prop1=None, prop2=None): | |
self.parent = parent | |
self._prop1 = prop1 | |
self._prop2 = prop2 | |
@property | |
def prop1(self): | |
try: | |
if self._prop1 is None: | |
return self.parent.prop1 | |
else: | |
return self._prop1 | |
except AttributeError as e: | |
return None | |
@property | |
def prop2(self): | |
try: | |
if self._prop2 is None: | |
return self.parent.prop2 | |
else: | |
return self._prop2 | |
except AttributeError as e: | |
return None | |
ag = Agro(None, prop1="nada") | |
ag2 = Agro(ag, prop1="nada2") | |
ag3 = Agro(ag2, prop2="youhou") | |
ag4 = Agro(ag3) | |
print(ag.prop1, ag.prop2, ag.__dict__) | |
print(ag2.prop1, ag2.prop2, ag2.__dict__) | |
print(ag3.prop1, ag3.prop2, ag3.__dict__) | |
print(ag4.prop1, ag4.prop2, ag4.__dict__) | |
# nada None {'parent': None, '_prop1': 'nada', '_prop2': None} | |
# nada2 None {'parent': <__main__.Agro object at 0x7fe08f87ccf8>, '_prop1': 'nada2', '_prop2': None} | |
# nada2 youhou {'parent': <__main__.Agro object at 0x7fe08f87cd30>, '_prop1': None, '_prop2': 'youhou'} | |
# nada2 youhou {'parent': <__main__.Agro object at 0x7fe08f87cd68>, '_prop1': None, '_prop2': None} | |
ag3._prop2 = "yaya" # the changes are repercuted dynamically, no copies are made | |
print(ag4.prop1, ag4.prop2, ag4.__dict__) | |
# nada2 yaya {'parent': <__main__.Agro object at 0x7fe08f87cd68>, '_prop1': None, '_prop2': None} |
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Lorsque l'on fait une copie simple, du style
self.prop1 = self.parent.prop1
, vu que c'est dans une instance de classe ce n'est pas par référence mais bien par valeur. Du coup lorsque l'on modifie le parent ca n'a pas d'inpact sur l'enfant