Javascript loop an array to find numbers divisible by 3

Question

I am needing to find the correct way to have javascript loop through an array, find all numbers that are divisible by 3, and push those numbers into a new array.

Here is what I have so far..

var array = [],
    threes = [];

function loveTheThrees(array) {
    for (i = 0, len = array.length; i < len; i++) {
    threes = array.push(i % 3);
  }
  return threes;
}

So if we pass through an array of [1, 2, 3, 4, 5, 6] through the function, it would push out the numbers 3 and 6 into the "threes" array. Hopefully this makes sense.

function loveTheThrees(a) { a.filter(function(a, i) {return a % 3 == 0}) } — Luis Masuelli
– Luis Masuelli, Commented Mar 30, 2016 at 18:43
You are pushing i%3 into array and then reassigning all of array to three. Suggestions are to use more meaningful names rather than array, learn about array and assignment operations in js — scrappedcola
– scrappedcola, Commented Mar 30, 2016 at 18:44

Nina Scholz · Accepted Answer · 2016-03-30 18:57:23Z

6

You can use Array#filter for this task.

filter() calls a provided callback function once for each element in an array, and constructs a new array of all the values for which callback returns a true value or a value that coerces to true. callback is invoked only for indexes of the array which have assigned values; it is not invoked for indexes which have been deleted or which have never been assigned values. Array elements which do not pass the callback test are simply skipped, and are not included in the new array.

function loveTheThrees(array) {
    return array.filter(function (a) {
        return !(a % 3);
    });
}
document.write('<pre>' + JSON.stringify(loveTheThrees([1, 2, 3, 4, 5, 6, 7, 8, 9, 10]), 0, 4) + '</pre>');

edited Mar 30, 2016 at 18:57

answered Mar 30, 2016 at 18:44

Nina Scholz

388k26 gold badges367 silver badges417 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Luis Masuelli Over a year ago

Damn you won by quicker fingers.

Rohit Shedage · Accepted Answer · 2016-06-24 00:59:46Z

1

console.log([1, 2, 3, 4, 5, 6, 7].filter(function(a){return a%3===0;}));

Array.filter() iterates over array and move current object to another array if callback returns true. In this case I have written a callback which returns true if it is divisible by three so only those items will be added to different array

edited Jun 24, 2016 at 0:59

answered Jun 23, 2016 at 22:46

Rohit Shedage

26.2k2 gold badges17 silver badges20 bronze badges

1 Comment

Rohit Shedage Over a year ago

Array.filter() iterates over array and move current object to another array if callback returns true. In this case I have written a callback which returns true if it is divisible by three so only those items will be added to different array

Mr. 14 · Accepted Answer · 2022-05-10 07:18:25Z

1

var array = [],
three = [];
 
function loveTheThrees(array) {
    for (i = 0, len = array.length; i < len; i++) {
        if(array[i] % 3 == 0){
            three.push(array[i]);
        }
    }
    return three;
}

edited May 10, 2022 at 7:18

Mr. 14

9,5466 gold badges42 silver badges56 bronze badges

answered Mar 30, 2016 at 18:45

Kim

558 bronze badges

Comments

user3839756 · Accepted Answer · 2016-03-30 19:16:33Z

0

Using Filter like suggested by Nina is defiantly the better way to do this. However Im assuming you are a beginner and may not understand callbacks yet, In this case this function will work:

function loveTheThrees(collection){
        var newArray = []
        for (var i =0; i< collection.length;i++){
            if (myArray[i] % 3 === 0){
                newArray.push(collection[i])
            }
        }
        return newArray;
    }

answered Mar 30, 2016 at 19:16

user3839756

8433 gold badges12 silver badges24 bronze badges

Comments

Shishir Arora · Accepted Answer · 2016-03-30 20:11:55Z

0

loveTheThrees=(arr)=>arr.filter(el=>Boolean(parseFloat(el)) && isFinite(el) && !Boolean(el%3))

es6 version + skipping non numbers

loveTheThrees([null,undefined,'haha',100,3,6])

Result: [3,6]

edited Mar 30, 2016 at 20:11

answered Mar 30, 2016 at 19:14

Shishir Arora

5,9934 gold badges33 silver badges36 bronze badges

Comments

Rajshekar Reddy · Accepted Answer · 2016-03-31 07:29:56Z

0

Check if the number is divisible by 3 if so then add it to array. Try this

function loveTheThrees(array) {
    for (i = 0, len = array.length; i < len; i++) {
      if(array[i] % 3 == 0){
        three.push(array[I]);
     }
  }

edited Mar 31, 2016 at 7:29

answered Mar 30, 2016 at 18:42

Rajshekar Reddy

19.1k4 gold badges45 silver badges64 bronze badges

1 Comment

Rajshekar Reddy Over a year ago

If anybody can edit this code block it will be helpful. I am on mobile app and no feature to add code block.. Thanks

MASTERKARR · Accepted Answer · 2016-05-19 22:58:46Z

0

var originalArray = [1, 2, 3, 4, 5, 6, 7, 8, 9];
function loveTheThrees(array1) {
  var threes = [];
  for (var i = 0; i < array1.length; i++) {
    if (array1[i] % 3 === 0) {
      threes.push(array1[i]);
    }
  }
  return threes;
}
loveTheThrees(originalArray);

edited May 19, 2016 at 22:58

answered May 19, 2016 at 22:51

MASTERKARR

12 bronze badges

1 Comment

Ajean Over a year ago

Welcome to Stack Overflow! While this code may answer the question, providing additional context regarding why and/or how this code answers the question improves its long-term value.

JulienRioux · Accepted Answer · 2018-05-24 16:38:28Z

0

In ES6:

const arr = [1, 33, 54, 30, 11, 203, 323, 100, 9];

// This single line function allow you to do it:
const isDivisibleBy3 = arr => arr.filter(val => val % 3 == 0);


console.log(isDivisibleBy3(arr));
// The console output is [ 33, 54, 30, 9 ]

answered May 24, 2018 at 16:38

JulienRioux

3,1322 gold badges28 silver badges40 bronze badges

Collectives™ on Stack Overflow

Javascript loop an array to find numbers divisible by 3

8 Answers 8

1 Comment

1 Comment

Comments

Comments

Comments

1 Comment

1 Comment

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

8 Answers 8

1 Comment

1 Comment

Comments

Comments

Comments

1 Comment

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related