org.nd4j.linalg.function

Class FunctionalUtils

java.lang.Object

org.nd4j.linalg.function.FunctionalUtils

public class FunctionalUtils
extends java.lang.Object

A simple util class for collapsing a Map in to a List of Pair where each item in the list will be an entry in the map represented by a Pair of the original key and value type.

Author:

Adam Gibson

Constructor Summary

Constructors

Constructor and Description
FunctionalUtils()

Method Summary

Modifier and Type	Method and Description
static <K,V> java.util.Map<K,Pair<java.util.List<V>,java.util.List<V>>>	cogroup(java.util.List<Pair<K,V>> left, java.util.List<Pair<K,V>> right) For each key in left and right, cogroup returns the list of values as a pair for each value present in left as well as right.
static <K,V> java.util.Map<K,java.util.List<V>>	groupByKey(java.util.List<Pair<K,V>> listInput) Group the input pairs by the key of each pair.
static <K,V> java.util.List<Pair<K,V>>	mapToPair(java.util.Map<K,V> map) Convert a map with a set of entries of type K for key and V for value in to a list of Pair

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

FunctionalUtils

public FunctionalUtils()

Method Detail

cogroup

public static <K,V> java.util.Map<K,Pair<java.util.List<V>,java.util.List<V>>> cogroup(java.util.List<Pair<K,V>> left,
                                                                                       java.util.List<Pair<K,V>> right)

For each key in left and right, cogroup returns the list of values as a pair for each value present in left as well as right.

Type Parameters:

K - the key type

V - the value type

Parameters:

left - the left list of pairs to join

right - the right list of pairs to join

Returns:

a map of the list of values by key for each value in the left as well as the right with each element in the pair representing the values in left and right respectively.

groupByKey

public static <K,V> java.util.Map<K,java.util.List<V>> groupByKey(java.util.List<Pair<K,V>> listInput)

Group the input pairs by the key of each pair.

Type Parameters:

K - the key type

V - the value type

Parameters:

listInput - the list of pairs to group

Returns:

a map representing a grouping of the keys by the given input key type and list of values in the grouping.

mapToPair

public static <K,V> java.util.List<Pair<K,V>> mapToPair(java.util.Map<K,V> map)

Convert a map with a set of entries of type K for key and V for value in to a list of Pair

Type Parameters:

K - the key type

V - the value type

Parameters:

map - the map to collapse

Returns:

the collapsed map as a List