DataFrame is a distributed collection of data organized into named columns. It is conceptually equivalent to a table in a relational database or a data frame in R/Python, but with richer optimizations under the hood. DataFrames can be constructed from a wide array of sources such as structured data files, tables in Hive, external databases, or existing RDDs
// Create SparkSession
import org.apache.spark.sql.SparkSession
val spark:SparkSession = SparkSession.builder()
.master("local[1]")
.appName("SparkByExamples.com")
.getOrCreate()
