Splitting Dataframe into two DataFrame

问题:

I have a dateframe which have unique as well as repeated records on the basis of number. Now i want to split the dataframe into two dataframe. In first dataframe i need to copy only unique rows and in second dataframe i want all repeated rows. For example

     id   name     number
     1    Shan     101
     2    Shan     101
     3    John     102
     4    Michel   103

The two splitted dataframe should be like

Unique

      id    name    number
      3     John    102
      4     Michel  103

Repeated

      id   name     number
      1    Shan     101
      2    Shan     101

回答1:

The solution you tried could probably get you there.

Your data looks like this

val df = sc.parallelize(Array(
     (1, "Shan",     101),
     (2, "Shan", 101),
     (3, "John", 102),
     (4, "Michel", 103)
     )).toDF("id","name","number")

Then you yourself suggest grouping and counting. If you do it like this

 val repeatedNames = df.groupBy("name").count.where(col("count")>1).withColumnRenamed("name","repeated").drop("count")

then you could actually get all the way by doing something like this afterwards:

 val repeated = df.join(repeatedNames, repeatedNames("repeated")===df("name")).drop("repeated")

 val distinct = df.except(repeated)

 repeated show
+---+----+------+
| id|name|number|
+---+----+------+
|  1|Shan|   101|
|  2|Shan|   101|
+---+----+------+

 distinct show
+---+------+------+
| id|  name|number|
+---+------+------+
|  4|Michel|   103|
|  3|  John|   102|
+---+------+------+

Hope it helps.