Takeshi Yamamuro created HIVEMALL-61:
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Summary: Support a function to convert a comma-separated string
into typed data and vice versa
Key: HIVEMALL-61
URL: https://issues.apache.org/jira/browse/HIVEMALL-61
Project: Hivemall
Issue Type: New Feature
Reporter: Takeshi Yamamuro
Priority: Minor
Currently, spark does not have this features (IMO this feature will not appear
as first-class ones in Spark) it is useful for ETL before ML processing.
e.x.)
{code}
scala> val ds1 = Seq("""1,abc""").toDS()
ds1: org.apache.spark.sql.Dataset[String] = [value: string]
scala> val schema = new StructType().add("a", IntegerType).add("b", StringType)
schema: org.apache.spark.sql.types.StructType =
StructType(StructField(a,IntegerType,true), StructField(b,StringType,true))
scala> val ds2 = ds1.select(from_csv($"value", schema))
ds2: org.apache.spark.sql.DataFrame = [csvtostruct(value): struct<a: int, b:
string>]
scala> ds2.printSchema
root
|-- csvtostruct(value): struct (nullable = true)
| |-- a: integer (nullable = true)
| |-- b: string (nullable = true)
scala> ds2.show
+------------------+
|csvtostruct(value)|
+------------------+
| [1,abc]|
+------------------+
{code}
A related discussion is here:
https://github.com/apache/spark/pull/13300#issuecomment-261962773
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