package com;

import java.util.Arrays;

import org.apache.spark.SparkConf;

import org.apache.spark.api.java.JavaDoubleRDD;

import org.apache.spark.api.java.JavaPairRDD;

import org.apache.spark.api.java.JavaRDD;

import org.apache.spark.api.java.JavaSparkContext;

import scala.Tuple2;

public class SimpleSpark {

public static void main(String[] args) {

SparkConf sconf = new SparkConf().setAppName("SimpleSpark").setMaster("local");

JavaSparkContext sc = new JavaSparkContext(sconf);

JavaRDD<String> data = sc.parallelize(Arrays.asList("a","b","c","a"));

JavaPairRDD<String, Integer> a = data.mapToPair(f -> new Tuple2<String, Integer>(f,1)).reduceByKey((a1,b1) -> a1+b1);

System.out.println(a.collect());

JavaRDD<Double> d = sc.parallelize(Arrays.asList(1.0,2.0,3.0));

JavaDoubleRDD dd = d.mapToDouble(f -> f*f);

System.out.println(dd.variance());

sc.close();

}

}