I fix a mistake in Steven D'Aprano interpretation.
class Person(object):
def __init__(self, name):
self._name = name
def getName(self):
print('fetch....')
return self._name
def setName(self, value):
print('change...')
self._name = value
def delName(self):
print('remove....')
del self._name
_name = property(getName, setName, delName, "name property docs")
x=Person("peter")
It can not initinalize.
File "<stdin>", line 9, in setName
File "<stdin>", line 8, in setName
RuntimeError: maximum recursion depth exceeded while calling a Python
object.
Steven D'Aprano interpretation:
10 Python finds the property _name
20 Python retrieves the getter, getName
30 Python runs the getName() method
40 which looks up self._name
50 go to 10
the right interpretation according to the error message:
10 python call __init__ method. self._name = name
20 python call setName method,
print('change...')
self._name = value
30 from self._name = value ,python call call setName method again
then we get a recursion error.
why i can not write _name = property(getName, setName, delName, "name
property docs") ?
Because you will have infinite recursion.
When you look up instance._name:
10 Python finds the property _name
20 Python retrieves the getter, getName
30 Python runs the getName() method
40 which looks up self._name
50 go to 10
and you get a recursion error.
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