Hi,
Using concat is one of the way.
But the + is more intuitive and easy to understand.
1427357...@qq.com
From: Shmuel Blitz
Date: 2018-03-26 15:31
To: 1427357...@qq.com
CC: spark?users; dev
Subject: Re: the issue about the + in column,can we support the string please?
Hi,
you can get the same with:
import org.apache.spark.sql.functions._
import sqlContext.implicits._
import org.apache.spark.sql.types.{IntegerType, StringType, StructField,
StructType}
val schema = StructType(Array(StructField("name", StringType),
StructField("age", IntegerType) ))
val lst = List(Row("Shmuel", 13), Row("Blitz", 23))
val rdd = sc.parallelize(lst)
val df = sqlContext.createDataFrame(rdd,schema)
df.withColumn("newName", concat($"name" , lit("abc")) ).show()
On Mon, Mar 26, 2018 at 6:36 AM, 1427357...@qq.com <1427357...@qq.com> wrote:
Hi all,
I have a table like below:
+---+---------+-----------+
| id| name|sharding_id|
+---+---------+-----------+
| 1|leader us| 10000|
| 3| mycat| 10000|
+---+---------+-----------+
My schema is :
root
|-- id: integer (nullable = false)
|-- name: string (nullable = true)
|-- sharding_id: integer (nullable = false)
I want add a new column named newName. The new column is based on "name" and
append "abc" after it. My code looks like:
stud_scoreDF.withColumn("newName", stud_scoreDF.col("name") + "abc" ).show()
When I run the code, I got the reslult:
+---+---------+-----------+-------+
| id| name|sharding_id|newName|
+---+---------+-----------+-------+
| 1|leader us| 10000| null|
| 3| mycat| 10000| null|
+---+---------+-----------+-------+
I checked the code, the key code is in arithmetic.scala. line 165.
It looks like:
override def doGenCode(ctx: CodegenContext, ev: ExprCode): ExprCode = dataType
match {
case dt: DecimalType =>
defineCodeGen(ctx, ev, (eval1, eval2) => s"$eval1.$$plus($eval2)")
case ByteType | ShortType =>
defineCodeGen(ctx, ev,
(eval1, eval2) => s"(${ctx.javaType(dataType)})($eval1 $symbol $eval2)")
case CalendarIntervalType =>
defineCodeGen(ctx, ev, (eval1, eval2) => s"$eval1.add($eval2)")
case _ =>
defineCodeGen(ctx, ev, (eval1, eval2) => s"$eval1 $symbol $eval2")
}
My issue is:
Can we add case StringType in this class to support string append please?
1427357...@qq.com
--
Shmuel Blitz
Big Data Developer
Email: shmuel.bl...@similarweb.com
www.similarweb.com
