スカラを使ってSparkを使ってループにマップする方法

Question

こんにちはスカラーのマップメソッドに "for"を使いたいです。

どうすればいいですか？例えば

ここでは、各ラインの私は、ランダムな単語を生成したい読み：

val rdd = file.map(line => (line,{ 
      val chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"; 
      val word = new String; 
      val res = new String; 
      val rnd = new Random; 
      val len = 4 + rnd.nextInt((6-4)+1); 

      for(i <- 1 to len){ 
       val char = chars(rnd.nextInt(51)); 
       word.concat(char.toString); 
      } 

      word; 
})) 

を私の現在の出力は、次のとおりです。

Array[(String, String)] = Array((1,""), (2,""), (3,""), (4,""), (5,""), (6,""), (7,""), (8,""), (9,""), (10,""), (11,""), (12,""), (13,""), (14,""), (15,""), (16,""), (17,""), (18,""), (19,""), (20,""), (21,""), (22,""), (23,""), (24,""), (25,""), (26,""), (27,""), (28,""), (29,""), (30,""), (31,""), (32,""), (33,""), (34,""), (35,""), (36,""), (37,""), (38,""), (39,""), (40,""), (41,""), (42,""), (43,""), (44,""), (45,""), (46,""), (47,""), (48,""), (49,""), (50,""), (51,""), (52,""), (53,""), (54,""), (55,""), (56,""), (57,""), (58,""), (59,""), (60,""), (61,""), (62,""), (63,""), (64,""), (65,""), (66,""), (67,""), (68,""), (69,""), (70,""), (71,""), (72,""), (73,""), (74,""), (75,""), (76,""), (77,""), (78,""), (79,""), (80,""), (81,""), (82,""), (83,""), (84,""), (85,""), (86... 

右側が空になった理由を私は知りません。

Answer 1

word.concatwordを変更しますが、新しいStringを返しません、あなたはword変数を作り、そこに新しい文字列を追加することができます。ここvarの必要はありません

var word = new String 
.... 
for { 
    ... 
    word += char 
    ... 
} 

Answer 2

。これは、1つのライナー

Seq.fill(len)(chars(rnd.nextInt(51))).mkString 

はこれが繰り返しchars(rnd.nextInt(51))を呼び出すことにより、長さlenのシャアのシーケンスを作成し、[文字列にそれを行います。私はそれをしようとすると、私はこのエラーエラーを受け取る

import org.apache.spark.rdd.RDD 
import scala.util.Random 

val chars = ('a' to 'z') ++ ('A' to 'Z') 

val rdd = file.map(line => { 
    val randomWord = { 
    val rnd = new Random 
    val len = 4 + rnd.nextInt((6 - 4) + 1) 
    Seq.fill(len)(chars(rnd.nextInt(chars.length-1))).mkString 
    } 
    (line, randomWord) 
})