Probably the easiest/closest way to do this would be with a UDF, something
like:
registerFunction("makeString", (s: Seq[String]) => s.mkString(","))
sql("SELECT *, makeString(c8) AS newC8 FROM jRequests")
Although this does not modify a column, but instead appends a new column.
Another more complicated way to do something like this would be by using the
applySchema function
<http://spark.apache.org/docs/latest/sql-programming-guide.html#programmatically-specifying-the-schema>
.
I'll note that, as part of the ML pipeline work, we have been considering
adding something like:
def modifyColumn(columnName, function)
Any comments anyone has on this interface would be appreciated!
Michael
On Tue, Nov 25, 2014 at 7:02 AM, Daniel Haviv <danielru...@gmail.com> wrote:
> Hi,
> I'm selecting columns from a json file, transform some of them and would
> like to store the result as a parquet file but I'm failing.
>
> This is what I'm doing:
>
> val jsonFiles=sqlContext.jsonFile("/requests.loading")
> jsonFiles.registerTempTable("jRequests")
>
> val clean_jRequests=sqlContext.sql("select c1, c2, c3 ... c55 from
> jRequests")
>
> and then I run a map:
> val
> jRequests_flat=clean_jRequests.map(line=>{((line(1),line(2),line(3),line(4),line(5),line(6),line(7),
> *line(8).asInstanceOf[Iterable[String]].mkString(",")*,line(9) ,line(10)
> ,line(11) ,line(12) ,line(13) ,line(14) ,line(15) ,line(16) ,line(17)
> ,line(18) ,line(19) ,line(20) ,line(21) ,line(22) ,line(23) ,line(24)
> ,line(25) ,line(26) ,line(27) ,line(28) ,line(29) ,line(30) ,line(31)
> ,line(32) ,line(33) ,line(34) ,line(35) ,line(36) ,line(37) ,line(38)
> ,line(39) ,line(40) ,line(41) ,line(42) ,line(43) ,line(44) ,line(45)
> ,line(46) ,line(47) ,line(48) ,line(49) ,line(50)))})
>
>
>
> 1. Is there a smarter way to achieve that (only modify a certain column
> without relating to the others, but keeping all of them)?
> 2. The last statement fails because the tuple has too much members:
> <console>:19: error: object Tuple50 is not a member of package scala
>
>
> Thanks for your help,
> Daniel
>
>
