subtractByKey

Class: matlab.compiler.mlspark.RDD
Namespace: matlab.compiler.mlspark

Return key-value pairs resulting from the set difference of keys between two RDDs

Syntax

result = subtractByKey(obj1,obj2,numPartitions)


Description

result = subtractByKey(obj1,obj2,numPartitions) returns a key-value pair RDD result resulting from the set difference of keys between obj1 and obj2. numPartitions specifies the number of partitions to create in the resulting RDD.

Input Arguments

obj1 — First input RDD

RDD object

An input RDD, specified as a RDD object.

obj2 — Second input RDD

RDD object

An input RDD, specified as a RDD object.

numPartitions — Number of partitions to create

scalar value

Number of partitions to create, specified as a scalar value.

Data Types: double

Output Arguments

result — RDD containing the set difference of keys between two RDDs

RDD object

A pipelined RDD containing the set difference of keys between two RDDs, returned as a RDD object.

Examples

Set Difference of Two RDDs by Key

%% Connect to Spark
sparkProp = containers.Map({'spark.executor.cores'}, {'1'});
conf = matlab.compiler.mlspark.SparkConf('AppName','myApp', ...
                        'Master','local[1]','SparkProperties',sparkProp);
sc = matlab.compiler.mlspark.SparkContext(conf);

%% subtractByKey
x = sc.parallelize({ {'a',1}, {'b',4}, {'b',5} , {'a',2} });
y = sc.parallelize({ {'a',3}, {'c',4} });
z = sc.parallelize({ {'a',2}, {'c',4} });
a = x.subtractByKey(y).collect(); % {{'b',4},{'b',5}}

Version History

Introduced in R2016b