Java-8 Pass multiple parameters of method into a stream

Question

Consider I have this method which take multiple parameters, and I want to make some simple calculation like count, sum, average, min, max, Take a look at this native example :

public static void calculate(int... param) {
    int sum = 0;
    for (int i : param) {
        sum += i;
    }
    System.out.println(sum);
}

How can I pass this parameters (int... param) in a Java-8 Stream and make this calculation?

Ash · Accepted Answer · 2017-03-03T11:42:10.680

If you want to do multiple checks on these params and only use one stream have a look at IntStream.summaryStatistics()

This will allow you to do this

IntSummaryStatistics statistics = IntStream.of(param).summaryStatistics();

statistics.getAverage();
statistics.getMax();
statistics.getMin();
statistics.getSum();
statistics.getCount();

IntSummaryStatistics is a very useful class for getting multiple statistics out of a stream.

Youcef LAIDANI · Answer 2 · 2017-03-03T15:56:21.540

6

You can use Array.stream like this :

//pass your method parameters in stream like this 
Arrays.stream(param).sum();
//--------------^---------

Here are some simple calculations:

public static void calculate(int... param) {
    //calculate sum
    Arrays.stream(param).sum();

    //calculate average
    Arrays.stream(param).average().getAsDouble();

    //count number of paramettres
    Arrays.stream(param).count();

    //find maximum
    Arrays.stream(param).max();

    //find minimum
    Arrays.stream(param).min();

    //find the first element
    Arrays.stream(param).sorted().findFirst();
}

edited Mar 03 '17 at 15:56

answered Mar 03 '17 at 10:45

Youcef LAIDANI

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3

Upvote for your answer. Also possible: IntStream.of(test).sum(); – kamehl23 Mar 03 '17 at 10:48
oh this is good @kamehl23 you can post it like an answer maybe this can help others – Youcef LAIDANI Mar 03 '17 at 10:50
1

Have you looked at when you have an IntStream you can use https://docs.oracle.com/javase/8/docs/api/java/util/stream/IntStream.html#summaryStatistics--, this will return an object which will give you the Sum, Average ect – Ash Mar 03 '17 at 10:53
1

Nice self-answer! – GhostCat Jun 29 '18 at 19:37

score 5 · Answer 3 · edited Mar 03 '17 at 10:55

5

Also possible: IntStream.of(param).sum();

edited Mar 03 '17 at 10:55

Youcef LAIDANI

55,661
15
90
140

answered Mar 03 '17 at 10:53

kamehl23

522
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6

Java-8 Pass multiple parameters of method into a stream

3 Answers3