Github user culler commented on a diff in the pull request:
https://github.com/apache/spark/pull/3066#discussion_r19733162
--- Diff:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/Row.scala
---
@@ -42,6 +44,31 @@ object Row {
* This method can be used to construct a [[Row]] from a [[Seq]] of
values.
*/
def fromSeq(values: Seq[Any]): Row = new GenericRow(values.toArray)
+
+ /**
+ * This method can be used to construct a [[Row]] from a [[Seq]] of
Strings,
+ * converting each item to the type specified in a [[StructType]] schema.
+ * Only primitive types can be used.
+ */
+ def fromStringsBySchema(strings: Seq[String], schema: StructType): Row =
{
+ val values = for {
+ (field, str) <- schema.fields zip strings
+ item = field.dataType match {
+ case IntegerType => str.toInt
+ case LongType => str.toLong
+ case DoubleType => str.toDouble
+ case FloatType => str.toFloat
+ case ByteType => str.toByte
+ case ShortType => str.toShort
+ case StringType => str
+ case BooleanType => (str != "")
+ case DateType => Date.valueOf(str)
+ case TimestampType => Timestamp.valueOf(str)
+ case DecimalType() => new BigDecimal(str)
+ }
+ } yield item
+ new GenericRow(values.toArray)
+ }
--- End diff --
It doesn't need to be a Row method. I will move it outside ( and worry
about the Boolean case.)
There is an issue lurking here, however. A SchemaRDD should have Rows
which match its schema. But mismatches generate no errors until the last
stage, e.g. when one collects the results of a query. My thought was that it
would be helpful to have a "safe" Row constructor which would check its data
against a schema and raise an error if they do not match (after applying
whatever implicit conversions are available. (Yes, this is a separate issue
and does not belong here.)
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