为什么尝试通过Python属性设置“点”会导致无限递归?
使用Python 3
import Task
myTask = Task.Task("Test",-5)
myTask.points = -7
print(myTask)
class Task:
def __init__(self,name="",points=0,times_done=0):
self.name = name
self.points = points
self.times_done = times_done
@property
def points(self):
return self.points
@points.setter
def points(self, points):
if (points < 0):
self.points = 0
else:
self.points = points
def __str__(self):
return "The task '" + self.name + "' is worth " + str(self.points) + " and has been completed " + str(self.times_done) + " times."
当它尝试使用值-5(应该通过属性将其设置为0)构建它时,它会无限地递归到set.function / decoration @ points.setter中的self.points =点.
谢谢!
解决方法:
因为self.points = …叫setter;在setter中,执行self.points = …来调用setter;重复递归直到堆栈溢出.
通过使用其他名称,您可以阻止递归:例如self._points.
或者不使用self.points = …,使用self .__ dict __ [‘points’] = ..(同样适用于getter):
@property
def points(self):
return self.__dict__['points']
@points.setter
def points(self, points):
if points < 0:
self.__dict__['points'] = 0
else:
self.__dict__['points'] = points
# self.__dict__['points'] = max(0, points)