CODEWITHSUNDEEP
scalaapache-sparkapache-spark-sql
smeeb
smeeb

Reputation: 29477

Creating a Spark DataFrame from a single string

I'm trying to take a hardcoded String and turn it into a 1-row Spark DataFrame (with a single column of type StringType) such that:

String fizz = "buzz"

Would result with a DataFrame whose .show() method looks like:

+-----+
| fizz|
+-----+
| buzz|
+-----+

My best attempt thus far has been:

val rawData = List("fizz")
val df = sqlContext.sparkContext.parallelize(Seq(rawData)).toDF()

df.show()

But I get the following compiler error:

java.lang.ClassCastException: org.apache.spark.sql.types.ArrayType cannot be cast to org.apache.spark.sql.types.StructType
    at org.apache.spark.sql.SQLContext.createDataFrame(SQLContext.scala:413)
    at org.apache.spark.sql.SQLImplicits.rddToDataFrameHolder(SQLImplicits.scala:155)

Any ideas as to where I'm going awry? Also, how do I set "buzz" as the row value for the fizz column?

Update:

Trying:

sqlContext.sparkContext.parallelize(rawData).toDF()

I get a DF that looks like:

+----+
|  _1|
+----+
|buzz|
+----+

Upvotes: 7

Views: 29275

Answers (2)

Martin Wunderlich
Martin Wunderlich

Reputation: 1884

In Java, the following works:

List<String> textList = Collections.singletonList("yourString");
SQLContext sqlContext = new SQLContext(sparkContext);
Dataset<Row> data = sqlContext
      .createDataset(textList, Encoders.STRING())
      .withColumnRenamed("value", "text");

Upvotes: 0

user6022341
user6022341

Reputation:

Try:

sqlContext.sparkContext.parallelize(rawData).toDF()

In 2.0 you can:

import spark.implicits._

rawData.toDF

Optionally provide a sequence of names for toDF:

sqlContext.sparkContext.parallelize(rawData).toDF("fizz")

Upvotes: 9

Related Questions