Hi,
I don't understand where the issue is...
➜ spark git:(master) ✗ cat csv-logs/people-1.csv
name,city,country,age,alive
Jacek,Warszawa,Polska,42,true
val df = spark.read.option("header", true).csv("csv-logs/people-1.csv")
val nameCityPairs = df.select('name, 'city).as[(String, String)]
scala> nameCityPairs.printSchema
root
|-- name: string (nullable = true)
|-- city: string (nullable = true)
Is this what you're after?
Pozdrawiam,
Jacek Laskowski
----
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Mastering Apache Spark 2.0 http://bit.ly/mastering-apache-spark
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On Fri, Aug 5, 2016 at 2:06 PM, Aseem Bansal <asmbans...@gmail.com> wrote:
> I need to use few columns out of a csv. But as there is no option to read
> few columns out of csv so
> 1. I am reading the whole CSV using SparkSession.csv()
> 2. selecting few of the columns using DataFrame.select()
> 3. applying schema using the .as() function of Dataset<Row>. I tried to
> extent org.apache.spark.sql.Encoder as the input for as function
>
> But I am getting the following exception
>
> Exception in thread "main" java.lang.RuntimeException: Only expression
> encoders are supported today
>
> So my questions are -
> 1. Is it possible to read few columns instead of whole CSV? I cannot change
> the CSV as that is upstream data
> 2. How do I apply schema to few columns if I cannot write my encoder?
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