PySpark with Juypter
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Spark is a fast and general engine for large-scale data processing. It was developed at UC Berkley in 2009 and can run programs up to 100x faster than Hadoop MapReduce in memory or 10x faster on disk. Spark uses Resilient Distributed Datasets (RDDs) as its basic abstraction, which allow data to be operated on in parallel. The document provides examples of using Spark for word count, SQL queries, and notebooks.
![Wordcount Example
//package org.myorg;!
import java.io.IOException;!
import java.util.*;!
!
import org.apache.hadoop.fs.Path;!
import org.apache.hadoop.conf.*;!
import org.apache.hadoop.io.*;!
import org.apache.hadoop.mapred.*;!
import org.apache.hadoop.util.*;!
!
public class WordCount {!
!
! public static class Map extends MapReduceBase implements Mapper<LongWritable, Text, Text,
IntWritable> {!
! ! private final static IntWritable one = new IntWritable(1);!
! ! private Text word = new Text();!
!
! ! public void map(LongWritable key, Text value, OutputCollector<Text, IntWritable>
output, Reporter reporter) throws IOException {!
! ! ! String line = value.toString();!
! ! ! StringTokenizer tokenizer = new StringTokenizer(line);!
! ! ! while (tokenizer.hasMoreTokens()) {!
! ! ! ! word.set(tokenizer.nextToken());!
! ! ! ! output.collect(word, one);!
! ! ! }!
! ! }!
! }!
!
! public static class Reduce extends MapReduceBase implements Reducer<Text, IntWritable,
Text, IntWritable> {!
! ! public void reduce(Text key, Iterator<IntWritable> values, OutputCollector<Text,
IntWritable> output, Reporter reporter) throws IOException {!
! ! ! int sum = 0;!
! ! ! while (values.hasNext()) {!
! ! ! ! sum += values.next().get();!
! ! ! }!
! ! ! output.collect(key, new IntWritable(sum));!
! ! }!
! }!
!
! public static void main(String[] args) throws Exception {!
! ! JobConf conf = new JobConf(WordCount.class);!
! ! conf.setJobName("wordcount");!
!
! ! conf.setOutputKeyClass(Text.class);!
! ! conf.setOutputValueClass(IntWritable.class);!
!
! ! conf.setMapperClass(Map.class);!
! ! //conf.setCombinerClass(Reduce.class);!
! ! conf.setReducerClass(Reduce.class);!
!
! ! conf.setInputFormat(TextInputFormat.class);!
! ! conf.setOutputFormat(TextOutputFormat.class);!
!
! ! FileInputFormat.setInputPaths(conf, new Path(args[0]));!
! ! FileOutputFormat.setOutputPath(conf, new Path(args[1]));!
!
! ! JobClient.runJob(conf);!
! }!
}
Hadoop MapReduce Spark Scala
val file = spark.textFile("hdfs://...")!
val counts = file.flatMap(line => line.split(" "))!
.map(word => (word, 1))!
.reduceByKey(_ + _)!
counts.saveAsTextFile("hdfs://...")
file = spark.textFile("hdfs://...")!
counts = file.flatMap(lambda line: line.split(" ")) !
.map(lambda word: (word, 1)) !
.reduceByKey(lambda a, b: a + b)!
counts.saveAsTextFile("hdfs://...")
Spark Python](https://image.slidesharecdn.com/intro-151117153250-lva1-app6892/85/PySpark-with-Juypter-15-320.jpg)
![Spark SQL and Dataframe Example
from pyspark.sql import SQLContext
sqlContext = SQLContext(sc)
!
# Create the DataFrame
df = sqlContext.read.json("people.json")
!
# Show the content of the DataFrame
df.show()
## age name
## null Michael
## 30 Andy
## 19 Justin
!
# Print the schema in a tree format
df.printSchema()
## root
## |-- age: long (nullable = true)
## |-- name: string (nullable = true)
!
# Select only the "name" column
df.select("name").show()
## name
## Michael
## Andy
## Justin
# Select everybody, but increment the age by 1
df.select(df['name'], df['age'] + 1).show()
## name (age + 1)
## Michael null
## Andy 31
## Justin 20
!
# Select people older than 21
df.filter(df['age'] > 21).show()
## age name
## 30 Andy
!
# Count people by age
df.groupBy("age").count().show()
## age count
## null 1
## 19 1
## 30 1](https://image.slidesharecdn.com/intro-151117153250-lva1-app6892/85/PySpark-with-Juypter-16-320.jpg)
PySpark with Juypter
- 1. By Tsai Li Ming PyData + Spark Meetup (SG) - 17 Nov 2015 http://about.me/tsailiming
- 2. Presentation and source codes are available here: http://github.com/tsailiming/pydatasg-17Nov2015
- 4. • Developed at UC Berkley in 2009. Open sourced in 2010. • Fast and general engine for large-scale data processing ! • Run programs up to 100x faster than Hadoop MapReduce in memory, or 10x faster on disk ! • Multi-step Directed Acrylic Graphs (DAGs). Many stages compared to just Hadoop Map and Reduce only. ! • Rich Scala, Java and Python APIs. R too! ! • Interactive Shell ! • Active development What is Spark?
- 5. Spark Stack
- 11. How Spark works
- 12. Resilient Distributed Datasets (RDDs) • Basic abstraction in Spark. Fault-tolerant collection of elements that can be operated on in parallel ! • RDDs can be created from local file system, HDFS, Cassandra, HBase, Amazon S3, SequenceFiles, and any other Hadoop InputFormat. ! • Different levels of caching: MEMORY_ONLY, MEMORY_AND_DISK, DISK_ONLY, OFF_HEAP, etc ! • Rich APIs for Transformations and Actions ! • Data Locality: PROCESS_LOCAL -> NODE_LOCAL -> RACK_LOCAL
- 13. RDD Operations map flatMap sortByKey filter union reduce sample join count groupByKey distinct saveAsTextFile reduceByKey mapValues first
- 14. Spark Example
- 15. Wordcount Example //package org.myorg;! import java.io.IOException;! import java.util.*;! ! import org.apache.hadoop.fs.Path;! import org.apache.hadoop.conf.*;! import org.apache.hadoop.io.*;! import org.apache.hadoop.mapred.*;! import org.apache.hadoop.util.*;! ! public class WordCount {! ! ! public static class Map extends MapReduceBase implements Mapper<LongWritable, Text, Text, IntWritable> {! ! ! private final static IntWritable one = new IntWritable(1);! ! ! private Text word = new Text();! ! ! ! public void map(LongWritable key, Text value, OutputCollector<Text, IntWritable> output, Reporter reporter) throws IOException {! ! ! ! String line = value.toString();! ! ! ! StringTokenizer tokenizer = new StringTokenizer(line);! ! ! ! while (tokenizer.hasMoreTokens()) {! ! ! ! ! word.set(tokenizer.nextToken());! ! ! ! ! output.collect(word, one);! ! ! ! }! ! ! }! ! }! ! ! public static class Reduce extends MapReduceBase implements Reducer<Text, IntWritable, Text, IntWritable> {! ! ! public void reduce(Text key, Iterator<IntWritable> values, OutputCollector<Text, IntWritable> output, Reporter reporter) throws IOException {! ! ! ! int sum = 0;! ! ! ! while (values.hasNext()) {! ! ! ! ! sum += values.next().get();! ! ! ! }! ! ! ! output.collect(key, new IntWritable(sum));! ! ! }! ! }! ! ! public static void main(String[] args) throws Exception {! ! ! JobConf conf = new JobConf(WordCount.class);! ! ! conf.setJobName("wordcount");! ! ! ! conf.setOutputKeyClass(Text.class);! ! ! conf.setOutputValueClass(IntWritable.class);! ! ! ! conf.setMapperClass(Map.class);! ! ! //conf.setCombinerClass(Reduce.class);! ! ! conf.setReducerClass(Reduce.class);! ! ! ! conf.setInputFormat(TextInputFormat.class);! ! ! conf.setOutputFormat(TextOutputFormat.class);! ! ! ! FileInputFormat.setInputPaths(conf, new Path(args[0]));! ! ! FileOutputFormat.setOutputPath(conf, new Path(args[1]));! ! ! ! JobClient.runJob(conf);! ! }! } Hadoop MapReduce Spark Scala val file = spark.textFile("hdfs://...")! val counts = file.flatMap(line => line.split(" "))! .map(word => (word, 1))! .reduceByKey(_ + _)! counts.saveAsTextFile("hdfs://...") file = spark.textFile("hdfs://...")! counts = file.flatMap(lambda line: line.split(" ")) ! .map(lambda word: (word, 1)) ! .reduceByKey(lambda a, b: a + b)! counts.saveAsTextFile("hdfs://...") Spark Python
- 16. Spark SQL and Dataframe Example from pyspark.sql import SQLContext sqlContext = SQLContext(sc) ! # Create the DataFrame df = sqlContext.read.json("people.json") ! # Show the content of the DataFrame df.show() ## age name ## null Michael ## 30 Andy ## 19 Justin ! # Print the schema in a tree format df.printSchema() ## root ## |-- age: long (nullable = true) ## |-- name: string (nullable = true) ! # Select only the "name" column df.select("name").show() ## name ## Michael ## Andy ## Justin # Select everybody, but increment the age by 1 df.select(df['name'], df['age'] + 1).show() ## name (age + 1) ## Michael null ## Andy 31 ## Justin 20 ! # Select people older than 21 df.filter(df['age'] > 21).show() ## age name ## 30 Andy ! # Count people by age df.groupBy("age").count().show() ## age count ## null 1 ## 19 1 ## 30 1
- 17. andypetrella/spark-notebook (forked from Scala notebook) Apache Zeppelin Notebooks for Spark
- 18. Actual Demo
- 20. Thank You!