我想收集数组列表中的数据框列值来进行一些计算，是否可能？

I am loading data from phoenix through this:

我正在通过以下方式从凤凰城加载数据:

val tableDF = sqlContext.phoenixTableAsDataFrame("Hbtable", Array("ID", "distance"), conf = configuration)

and want to carry out the following computation on the column values distance:

并希望对列值距离进行以下计算:

val list=Array(10,20,30,40,10,20,0,10,20,30,40,50,60)//list of values from the column distance
val first=list(0)
val last=list(list.length-1)
var m = 0; 
for (a <- 0 to list.length-2) {
  if (list(a + 1) < list(a) && list(a+1)>=0)
  {
     m = m + list(a)
  } 
}
val totalDist=(m+last-first)

1 个解决方案

#1

You can do something like this. It returns Array[Any]

你可以做这样的事情。它返回Array [Any]

`val array = df.select("distance").rdd.map(r => r(0)).collect()

If you want to get the data type properly, then you can use. It returns the Array[Int]

如果要正确获取数据类型,则可以使用。它返回Array [Int]

val array = df.select("distance").rdd.map(r => r(0).asInstanceOf[Int]).collect()

#1