Reputation: 25396
I have the following code from the Spark example website, trying to run it from Eclipse, but it seems the code doesn't even compile.
import org.apache.spark._
import org.apache.spark.SparkContext._
object DataFrameExample {
def main(args: Array[String]) {
case class Person(name: String, age: Int)
val conf = new SparkConf().setAppName("wordCount"); //.setMaster("local")
conf.setMaster("local");
val sc = new SparkContext(conf)
val sqlContext = new org.apache.spark.sql.SQLContext(sc)
import sqlContext._
import sqlContext.implicits._
val people = sc.textFile("examples/src/main/resources/people.txt").map(_.split(",")).map(p => Person(p(0), p(1).trim.toInt)).toDF()
people.registerTempTable("people")
val teenagers = sqlContext.sql("SELECT name, age FROM people WHERE age >= 13 AND age <= 19")
// The results of SQL queries are DataFrames and support all the normal RDD operations.
// The columns of a row in the result can be accessed by field index:
teenagers.map(t => "Name: " + t(0)).collect().foreach(println)
// or by field name:
teenagers.map(t => "Name: " + t.getAs[String]("name")).collect().foreach(println)
// row.getValuesMap[T] retrieves multiple columns at once into a Map[String, T]
teenagers.map(_.getValuesMap[Any](List("name", "age"))).collect().foreach(println)
// Map("name" -> "Justin", "age" -> 19)
}
}
But then I got the following errors. Did I miss anything here? Thanks!
The same error (as text, from IntelliJ)
Error:(18, 93) No TypeTag available for Person val people = sc.textFile("examples/src/main/resources/people.txt").map(_.split(",")).map(p => Person(p(0), p(1).trim.toInt)).toDF() ^
Upvotes: 0
Views: 1305
Reputation: 13008
Move the definition of class Person
:
case class Person(name: String, age: Int)
object DataFrameExample {
def main(args: Array[String]) {
// [...]
}
}
That definition must be outside of the method using it.
As for the reason: Have a look at this, a quote from there:
2- Move case class outside of the method:
case class, by use of which you define the schema of the DataFrame, should be defined outside of the method needing it.
And it references https://issues.scala-lang.org/browse/SI-6649
Upvotes: 2