Numbers divisible by 3 in JavaScript

Question

I'm trying to make a more advanced scientific calculator. I am having trouble figuring out how to do this type of calculation. I have an array of numbers and I want to check which of the given numbers are divisible by 3.

I would like both the collection of numbers divisible by 3 and the count of those numbers.

For example, on input of:

const collection = [
    { text: "0", value: 0 },
    { text: "1", value: 1 },
    { text: "2", value: 2 },
    { text: "3", value: 3 },
    { text: "4", value: 4 },
    { text: "5", value: 5 },
    { text: "6", value: 6 },
    { text: "7", value: 7 },
    { text: "8", value: 8 },
    { text: "9", value: 9 },
    { text: "10", value: 10 },
    { text: "11", value: 11 },
    { text: "12", value: 12 },
];

I would like to get output like:

"There are 5 divisible numbers by 3: 0, 3, 6, 9, 12"

How can I do that?

Does this answer your question? [What does % do in JavaScript?](https://stackoverflow.com/questions/8900652/what-does-do-in-javascript) — Oleg Valter is with Ukraine, Nov 09 '21 at 19:58

score 1 · Answer 1 · answered Nov 09 '21 at 13:00

1

Use the modulo operator with for loops, denoted by %

answered Nov 09 '21 at 13:00

Anuraag Barde

399
3
9

0stone0 · Answer 2 · 2021-11-09T13:08:12.000

I have an array of numbers and I want to check which of the given numbers are divisible by 3.

You have an array of objects holding a Number on the value key.

We can get the desired output by

filter() only devisible by 3
filter(c => c.value % 3 === 0)
map() to only get number from value key
join() to separate results with an comma

const collection = [{ text: "0", value: 0 }, { text: "1", value: 1 }, { text: "2", value: 2 }, { text: "3", value: 3 }, { text: "4", value: 4 }, { text: "5", value: 5 }, { text: "6", value: 6 }, { text: "7", value: 7 }, { text: "8", value: 8 }, { text: "9", value: 9 }, { text: "10", value: 10 }, { text: "11", value: 11 }, { text: "12", value: 12 }, ];

let res = collection.filter(c => c.value % 3 === 0).map(o => o.value);
console.log(`There are ${res.length} divisible numbers by 3: ${res.join(', ')}`);

Result

There are 5 divisible numbers by 3: 0, 3, 6, 9, 12

If we want to exclude 0, we can change te filter() to:

let res = collection.filter(c => c.value > 0 && c.value % 3 === 0).map(o => o.value);

score 1 · Answer 3 · answered Nov 09 '21 at 13:07

You can use filter method to filter out objects containing number divisible by 3, using modulo (%) operator. I have used map as well, to create an array of values, instead of objects.

const collection = [
    { text: "0", value: 0 },
    { text: "1", value: 1 },
    { text: "2", value: 2 },
    { text: "3", value: 3 },
    { text: "4", value: 4 },
    { text: "5", value: 5 },
    { text: "6", value: 6 },
    { text: "7", value: 7 },
    { text: "8", value: 8 },
    { text: "9", value: 9 },
    { text: "10", value: 10 },
    { text: "11", value: 11 },
    { text: "12", value: 12 },
];

let divby3 = collection.filter((x)=>x.value % 3 === 0).map((x)=>x.value)

console.log(`There are ${divby3.length} divisible numbers by 3: ${divby3}`)

@Navro please check this out! – TechySharnav Nov 11 '21 at 04:24 — TechySharnav, Nov 11 '21 at 04:24

score 0 · Answer 4 · answered Nov 09 '21 at 13:01

0

You can use the % operator. So if number%3 ==0 means it divides

answered Nov 09 '21 at 13:01

Omle

51
5

score 0 · Answer 5 · answered Nov 09 '21 at 13:02

Check out Remainder (%) operator.

Using it you can extract all numbers divisible by 3:

const divisible = collection.map(x => x.value).filter(x => !(x % 3))

And print them:

console.log(`There are ${divisible.length} divisible numbers by 3: ${divisible.join(', ')}`)
// There are 5 divisible numbers by 3: 0, 3, 6, 9, 12

Numbers divisible by 3 in JavaScript

5 Answers5

Result