성능 향상을 위해 Python 지연 초기화를 사용하는 예에 대한 자세한 설명

class Circle(object): 
  def init(self, radius): 
    self.radius = radius 
  
  @property
  def area(self): 
    return 3.14 * self.radius ** 2
  
c = Circle(4) 
print c.radius 
print c.area

class LazyProperty(object):
  def init(self, func):
    self.func = func
  def get(self, instance, owner):
    if instance is None:
      return self
    else:
      value = self.func(instance)
      setattr(instance, self.func.name, value)
      return value
import math
class Circle(object):
  def init(self, radius):
    self.radius = radius
  @LazyProperty
  def area(self):
    print 'Computing area'
    return math.pi * self.radius ** 2
  @LazyProperty
  def perimeter(self):
    print 'Computing perimeter'
    return 2 * math.pi * self.radius

>>> c = Circle(2)
>>> print c.area
Computing area
12.5663706144
>>> print c.area
12.5663706144