Java 8 frequency Object in array [duplicate]

Question

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• Word frequency count Java 8 8 answers

I have an Object[] array

I need to create map Map<Obejct, Integer>, where Integer value contains frequency of key Object in array.

How can i do it in java 8 style, using Collectors?

Answer 1

You can do (I hope I don't have any typos) :

Map<Object,Long> map = Stream.of(array)
                                .collect(Collectors.groupingBy(o -> o,
                                                               Collectors.counting()));

This should group the elements of the array by equality and count the number of Objects in each group.