Did you try:
val data = indexed_files.groupByKey
val *modified_data* = data.map { a =>
var name = a._2.mkString(",")
(a._1, name)
}
*modified_data*.foreach { a =>
var file = sc.textFile(a._2)
println(file.count)
}
Thanks
Best Regards
On Wed, Jul 22, 2015 at 2:18 AM, MorEru wrote:
> I have a number of CSV files and need to combine them into a RDD by part of
> their filenames.
>
> For example, for the below files
> $ ls
> 20140101_1.csv 20140101_3.csv 20140201_2.csv 20140301_1.csv
> 20140301_3.csv 20140101_2.csv 20140201_1.csv 20140201_3.csv
>
> I need to combine files with names 20140101*.csv into a RDD to work on it
> and so on.
>
> I am using sc.wholeTextFiles to read the entire directory and then grouping
> the filenames by their patters to form a string of filenames. I am then
> passing the string to sc.textFile to open the files as a single RDD.
>
> This is the code I have -
>
> val files = sc.wholeTextFiles("*.csv")
> val indexed_files = files.map(a => (a._1.split("_")(0),a._1))
> val data = indexed_files.groupByKey
>
> data.map { a =>
> var name = a._2.mkString(",")
> (a._1, name)
> }
>
> data.foreach { a =>
> var file = sc.textFile(a._2)
> println(file.count)
> }
>
> And I get SparkException - NullPointerException when I try to call
> textFile.
> The error stack refers to an Iterator inside the RDD. I am not able to
> understand the error -
>
> 15/07/21 15:37:37 INFO TaskSchedulerImpl: Removed TaskSet 65.0, whose tasks
> have all completed, from pool
> org.apache.spark.SparkException: Job aborted due to stage failure: Task 1
> in
> stage 65.0 failed 4 times, most recent failure: Lost task 1.3 in stage 65.0
> (TID 115, 10.132.8.10): java.lang.NullPointerException
> at
> $iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$anonfun$1.apply(:33)
> at
> $iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$anonfun$1.apply(:32)
> at scala.collection.Iterator$class.foreach(Iterator.scala:727)
> at scala.collection.AbstractIterator.foreach(Iterator.scala:1157)
> at
>
> org.apache.spark.rdd.RDD$$anonfun$foreach$1$$anonfun$apply$28.apply(RDD.scala:870)
> at
>
> org.apache.spark.rdd.RDD$$anonfun$foreach$1$$anonfun$apply$28.apply(RDD.scala:870)
> at
>
> org.apache.spark.SparkContext$$anonfun$runJob$5.apply(SparkContext.scala:1765)
> at
>
> org.apache.spark.SparkContext$$anonfun$runJob$5.apply(SparkContext.scala:1765)
>
> However, when I do sc.textFile(data.first._2).count in the spark shell, I
> am
> able to form the RDD and able to retrieve the count.
>
>
>
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