笛卡尔变换在标量火花中的奇异行为

Question

我在Scala Spark中使用笛卡尔变换，我有一组6个坐标，如下所示。

coord.collect
res114: Array[(Float, Float, Float)] = Array(
  (43.13,-67.331,-18.137),     
  (63.914,-67.078,-16.894), 
  (23.13,-60.341,-28.117),     
  (53.914,-67.028,-16.824), 
  (63.11,-69.311,-18.117),     
  (61.924,-67.068,-16.874)
)

coord.cartesian.com为我提供了以下输出。

coord.cartesian(coord).collect
res118: Array[((Float, Float, Float), (Float, Float, Float))] = Array(
  ((43.13,-67.331,-18.137),(43.13,-67.331,-18.137)), 
  ((43.13,-67.331,-18.137),(63.914,-67.078,-16.894)), 
  ((43.13,-67.331,-18.137),(23.13,-60.341,-28.117)), 
  ((43.13,-67.331,-18.137),(53.914,-67.028,-16.824)), 
  ((43.13,-67.331,-18.137),(63.11,-69.311,-18.117)), 
  ((63.914,-67.078,-16.894),(43.13,-67.331,-18.137)), 
  ((63.914,-67.078,-16.894),(63.914,-67.078,-16.894)), 
  ((63.914,-67.078,-16.894),(23.13,-60.341,-28.117)),  ((...

为什么第六个元素不是（（43.13，-67.331，-18.137），（61.924，-67.068，-16.874））？

我是否有某种不让我按顺序选择值的洗牌？

Answer 1

顺序无关紧要，因为没有顺序保证（当涉及到混洗时）。

只要您总共检索到36个正确的结果集（不考虑顺序），一切都很好。