Scala and Spark for Big Data Analytics

First

Gets the first record in the RelationalGroupeddataset.

The first API has several implementations, as follows. The exact API used depends on the specific use case:

def first(columnName: String): ColumnAggregate function: returns the first value of a column in a group.def first(e: Column): ColumnAggregate function: returns the first value in a group.def first(columnName: String, ignoreNulls: Boolean): ColumnAggregate function: returns the first value of a column in a group.def first(e: Column, ignoreNulls: Boolean): ColumnAggregate function: returns the first value in a group.

Let's look at an example of invoking first on the DataFrame to output the first row:

import org.apache.spark.sql.functions._scala> statesPopulationDF.select(first("State")).show ...