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scalaapache-sparkhadoop2

Spark write result of Array[Array[Any]] to file


I have input like following sample

3070811,1963,1096,,"US","CA",,1,
3022811,1963,1096,,"US","CA",,1,56
3033811,1963,1096,,"US","CA",,1,23

After writing replacing the empty chars with 0, i am trying to write the result to textFile and i am getting

scala> result.saveAsTextFile("data/result")
<console>:34: error: value saveAsTextFile is not a member of Array[Array[Any]]
              result.saveAxtFile("data/result")

Here is the solution

scala> val file2 = sc.textFile("data/file.txt")
scala> val mapper = file2.map(x => x.split(",",-1))
scala> val result = mapper.map(x => x.map(x => if(x.isEmpty) 0 else x)).collect()
result: Array[Array[Any]] = Array(Array(3070811, 1963, 1096, 0, "US", "CA", 0, 1, 0), Array(3022811, 1963, 1096, 0, "US", "CA", 0, 1, 56), Array(3033811, 1963, 1096, 0, "US", "CA", 0, 1, 23))
scala> result.saveAsTextFile("data/result")
<console>:34: error: value saveAsTextFile is not a member of Array[Array[Any]]
              result.saveAsTextFile("data/result")

I have also tried following and it failed as well

scala> val output = result.map(x => (x(0),x(1),x(2),x(3), x(4), x(5), x(7), x(8)))
output: Array[(Any, Any, Any, Any, Any, Any, Any, Any)] = Array((3070811,1963,1096,0,"US","CA",1,0), (3022811,1963,1096,0,"US","CA",1,56), (3033811,1963,1096,0,"US","CA",1,23))

scala> output.saveAsTextFile("data/output")
<console>:36: error: value saveAsTextFile is not a member of Array[(Any, Any, Any, Any, Any, Any, Any, Any)]
              output.saveAsTextFile("data/output")

and then added following and it failed as well

scala> output.mapValues(_.toList).saveAsTextFile("data/output")
<console>:36: error: value mapValues is not a member of Array[(Any, Any, Any, Any, Any, Any, Any, Any)]
              output.mapValues(_.toList).saveAsTextFile("data/output")

How can i view in console or in a result file the contents of result or output variables. Missing something basic here.

Update 1

per Shankar Koirala i have removed .collect and then performed save.

scala> val result = mapper.map(x => x.map(x => if(x.isEmpty) 0 else x))

and this is resulting in this output

[Ljava.lang.Object;@7a1167b6
[Ljava.lang.Object;@60d86d2f
[Ljava.lang.Object;@20e85a55

Update 1.a

Picked up the updated answer and it is giving the correct data

scala> val result = mapper.map(x => x.map(x => if(x.isEmpty) 0 else x).mkString(","))
result: org.apache.spark.rdd.RDD[String] = MapPartitionsRDD[29] at map at <console>:31

scala> result.saveAsTextFile("data/mkstring")

result

3070811,1963,1096,0,"US","CA",0,1,0
3022811,1963,1096,0,"US","CA",0,1,56
3033811,1963,1096,0,"US","CA",0,1,23

Update 2

scala> val output = result.map(x => (x(0),x(1),x(2),x(3), x(4), x(5), x(7), x(8)))
output: org.apache.spark.rdd.RDD[(Any, Any, Any, Any, Any, Any, Any, Any)] = MapPartitionsRDD[27] at map at <console>:33

scala> output.saveAsTextFile("data/newOutPut")

and i got this result

(3070811,1963,1096,0,"US","CA",1,0)
(3022811,1963,1096,0,"US","CA",1,56)
(3033811,1963,1096,0,"US","CA",1,23)

Solution

  • The below code returns Array[Array[Any]]

    val result = mapper.map(x => x.map(x => if(x.isEmpty) 0 else x)).collect()
    

    Since there is no method saveAsTextFile in Array

    It is available in RDD so you don't need to collect the output

    val result = mapper.map(x => x.map(x => if(x.isEmpty) 0 else x))
    

    Use mkstring() to convert to string and write in file

    val result = mapper.map(x => x.map(x => if(x.isEmpty) 0 else x).mkString(","))
    

    You should also stop using collect() which brings all the data to driver which can cause memory issue if data is large.

    Hope this helps!