如何實現 Python __lt__ __gt__ 自定義（過載）運算子？

Python 擁有魔法方法來定義運算子的過載行為。可以透過為 __lt__、__le__、__gt__、__ge__、__eq__ 和 __ne__ 魔法方法提供定義來過載比較運算子（<、<=、>、>=、== 和 !=）。以下程式過載 < 和 > 運算子來比較 distance 類的物件。 

class distance:
  def __init__(self, x=5,y=5):
    self.ft=x
    self.inch=y

  def __eq__(self, other):
    if self.ft==other.ft and self.inch==other.inch:
      return "both objects are equal"
    else:
      return "both objects are not equal"

  def __lt__(self, other):
    in1=self.ft*12+self.inch
    in2=other.ft*12+other.inch
    if in1<in2:
      return "first object smaller than other"
    else:
      return "first object not smaller than other"

  def __gt__(self, other):
    in1=self.ft*12+self.inch
    in2=other.ft*12+other.inch
    if in1<in2:
      return "first object greater than other"
    else:
      return "first object not greater than other"

d1=distance(5,5)
d2=distance()
print (d1>d2)
d3=distance()
d4=distance(6,10)
print (d1<d2)
d5=distance(3,11)
d6=distance()
print(d5<d6)

結果展示了 __lt__ 和 _gt__ 魔法方法的實現

first object not greater than other
first object not smaller than other
first object smaller than other

Pythonista

更新於: 02-Mar-2020

3000+ 瀏覽

啟動您的 職業

完成課程，獲得認證

開始