ReTweetRec.scala

package retweetrec

import scala.xml.XML
import java.net.URL
import java.io.InputStream

object ReTweetRec {

  def getFollowers(id: String) = {
    val data = new URL("http://twitter.com/followers/ids/" + id + ".xml").getContent
    val xml = XML.load(data.asInstanceOf[InputStream])
    for (id <- xml \ "id") yield id.text
  }

  def main(args : Array[String]) : Unit = {
    val user1 = args(0)
    val user2 = args(1)
    val followers1 = getFollowers(user1)
    val followers2 = getFollowers(user2)
    val (same, diff) = followers1.partition(followers2.contains)
    val sameSize = same.toList.size
    val diffSize = diff.toList.size
    println("Followers of both " + user1 + " and " + user2 + ": " + sameSize)
    println("Followers of " + user1 + " not following " + user2 + ": " + diffSize)
    val percentSame = sameSize / followers1.size.toFloat
    println("Percentage of shared followers %.1f%%".format(percentSame * 100))
    println("Recommendation: " + (if (percentSame > 1/3f) "don't retweet!" else "retweet!"))
  }

}