Question 73948 in Reactjs Question posted in
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How to return sum of n highest values in an array? – Reactjs

import React from 'react';
import ReactDOM from 'react-dom';
import { useState } from 'react';

const Dice = () => {
    const [dice, setDice] = useState([1, 1, 2, 2]);

    function rollDice() {
        return Array.from({length: 4}, () => Math.floor(Math.random() * 6) + 1);
    }


    const handleClick = () => {
        setDice(rollDice());
    }

    const rolls = dice.map(die => <span> {die} </span> );

    const stat = dice.splice(Math.min(...dice)).reduce(function(a, b) {
        return a + b;
    });

    return (
        <>
            <button onClick={handleClick}>Roll for stats</button>

            <div>
                Your rolls are: {rolls}
            </div>
            
            <div>
                Your stat is: {stat}
            </div>
        </>
    );
}

export default Dice;

if (document.getElementById('dice')) {
    ReactDOM.render(<Dice />, document.getElementById('dice'));
}

So I’m making online DnD and I’m testing out the dice rolls for stats, first few iterations went fine and then it returned the sum of the wrong numbers, it "randomly" removes the numbers I need and returns the wrong sum. I am doing this after being away from the code world for awhile so I’m sorry if it’s something dumb but i really can’t figure out what’s the issue.

Tags:

3

Answers


  1. Chosen as BEST ANSWER
    0

    This does the trick, changing stat to a function and running the splice method on a copy of the dice array:

    const stat = () => {
    let smallestRoll = Math.min(...dice)
    let indexOfSmallest = dice.indexOf(smallestRoll)
    let diceCopy = [...dice]

    diceCopy.splice(indexOfSmallest, 1)

    let sum = diceCopy.reduce(function(a, b) {
        return a + b;
    });

    return sum;
}

    and returning it as a function:

    return (
    <>
        <div>
            Your stat is: {stat()}
        </div>
    </>
);

    Thank you for all your help!


  2. 0

    You can use reduce for this

    function sumOfNHighestValues(arr: number[], n: number): number {
  const sortedArr = arr.sort((a, b) => b - a); // sort the array in descending order
  const slicedArr = sortedArr.slice(0, n); // slice the first n elements
  const sum = slicedArr.reduce((total, num) => total + num, 0); // sum the sliced elements
  return sum;
}

// example usage
const arr = [5, 2, 8, 3, 9, 4];
const n = 3;
const result = sumOfNHighestValues(arr, n);
console.log(result); // output: 21 (sum of 9, 8, and 5)
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  3. 0

    you can try es6 syntax, extension operator(…)

    var arr = [22,13,6,55,30];
console.log(Math.max(...arr)); // 55
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