Is There Possibility of Sum of Arraylist Without Looping

How do i find Sum of values in an ArrayList (Java )?

Have you tried iterating over the list and adding those numbers?

List<MSSVectorAlg> vectors = new ArrayList<MSSVectorAlg>();

int xTotal = 0, yTotal = 0, zTotal = 0;
for (MSSVectorAlg vector : vectors)
{
   xTotal  += vector.getX();
   yTotal  += vector.getY();
   zTotal  += vector.getZ();
}

Sum all the elements java arraylist

Two ways:

Use indexes:

double sum = 0;
for(int i = 0; i < m.size(); i++)
    sum += m.get(i);
return sum;

Use the "for each" style:

double sum = 0;
for(Double d : m)
    sum += d;
return sum;

How do you find the sum of all numbers in a set in Java?

Aside from using loops explicitly, for List<Integer> list you can do:

int sum = list.stream().mapToInt(Integer::intValue).sum();

If it's an int[] arr then do:

int sum = IntStream.of(arr).sum();

This is based on the use of streams.

Or you can do this simple one liner loop:

int sum = 0;
for (Integer e : myList) sum += e;

Even better, write a function and reuse it:

public int sum(List<Integer> list) {
    int sum = 0;
    for (Integer e : list) sum += e;

    return sum;
}

Adding the elements of a double[] array without using a loop in java

No, you can't calculate the sum of a list of values in one step. Even if there was an API method or some library that offered a sum function, it would use loops internally. The complexity of the sum algorithm is O(n) (for single CPUs).

A way out could be using parallel computing, but that's a theoretical approach to answer your question. You'd need at least as many CPUs as array cells to calculate the sum in on step. (Or one fictional CPU with as many FP registers as array values).

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Before you start looking at API's of Java or other libraries:

 public static double sum(double...values) {
   double result = 0;
   for (double value:values)
     result += value;
   return result;
 }

Usage:

 double sum = sum(array);  // this is in your main code -> no loop (visible)

How to get the sum of an Integer arraylist?

Here's how you sum a Collection using java 8:

import java.util.ArrayList;
import java.util.List;

public class Solution {

    public static void main(String args[]) throws Exception {
        List<Integer> numbers = new ArrayList<>();
        numbers.add(1);
        numbers.add(3);
        numbers.add(5);

        System.out.println(numbers.stream().mapToInt(value -> value).sum());
    }
}

In your code, you would do this to the grade list. You can set this to gradetotal after your loop.

value -> value is saying "take each argument and return it". stream() returns a Stream which doesn't have sum(). mapToInt returns an IntStream which does have sum(). That value -> value tells the code how to convert each element in the Stream into an Integer. Because each element is already an Integer, we merely have to return each element.

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