Spark Scala - Split Map, Getkey and so on - scala

Question

I have a text file wich contains the following :
A>B,C,D
B>A,C,D,E
C>A,B,D,E
D>A,B,C,E
E>B,C,D
I would like to write a Spark-Scala script to obtain the following :
(For each left member, we give all right members.)
(A,B)
(A,C)
(A,D)
(B,A)
(B,C)
(B,D)
(B,E)
...
I tried to go through the map and get the keys to feed a new map with my results but it did not work.
Here is my code (more like pseudo code):
import scala.io.Source
// Loading file
val file = sc.textFile("friends.txt")
// MAP
// A;B
// A;C
// ...
var associations_persons_friends:Map[Char,Char] = Map()
var lines = file.map(line=>line.split(">"))
for (line <- lines)
{
val person = line.key
for (friend <- line.value.split(","))
{
associations_persons_friends += (person -> friend)
}
}
associations_persons_friends.collect()
val rdd = sc.parallelize(associations_persons_friends)
rdd.foreach(println)
// GROUP
// For each possible pair, all associated values
// AB;B-C-D-A-C-D-E
// REDUCE
// For each pair we keep occurences >= 2
// AB;C-D
I wonder if it is possible to write basic code like this in Spark-Scala because I can't find any answer to my needs on the web.
Thanks for help.

Answer 1

you can achieve your requirement with the combination of map and flatMap as
val rdd = sc.textFile("path to the text file")
rdd.map(line => line.split(">")).flatMap(array => array(1).split(",").map(arr => (array(0), arr))).foreach(println)
You should have output as
(A,B)
(A,C)
(A,D)
(B,A)
(B,C)
(B,D)
(B,E)
(C,A)
(C,B)
(C,D)
(C,E)
(D,A)
(D,B)
(D,C)
(D,E)
(E,B)
(E,C)
(E,D)
I hope the answer is helpful