How can I use modulo operator (%) in JavaScript?

javascript char character

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Solution 1

It's the remainder operator and is used to get the remainder after integer division. Lots of languages have it. For example:

10 % 3 // = 1 ; because 3 * 3 gets you 9, and 10 - 9 is 1.

Apparently it is not the same as the modulo operator entirely.

Solution 2

That would be the modulo operator, which produces the remainder of the division of two numbers.

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Author by

Ziyaddin Sadigov

Updated on July 24, 2020

Comments

Ziyaddin Sadigov almost 4 years

How can I use modulo operator (%) in calculation of numbers for JavaScript projects?
MarioDS about 11 years

You can fit 3 exactly 3 times in 9. If you would add 3 one more time to 9, you would end up with 12. But you were dividing 10, so instead you say it's 3 times 9 with the remainder being 1. That's what modulo gets you.
Codebeat about 10 years

I think it is better to explain it this way: Modulo is the difference left when dividing a value. You can use this to calculate listing lists with items, for example: 10 % 10 gives you 0. When it is 0 you know there a 10 items in a list. For example 20 % 10 gives you the same value, 0, another 10 items in a list......
Lucero over 9 years

There is no "integer division" operator in JS AFAIK; 10 / 3 will result in 3.333.... You need to truncate the fraction, for instance by using Math.floor().
MarioDS over 9 years

@Lucero you're right, I never realised that! I just assumed it used the same basic operator available in many languages.
Lucero over 9 years

@MDeSchaepmeester, well it kind of is using the same basic operator as in other languages, but it lacks a specific integer primitive. JS natively only has "number" primitives which are floating-point, and thus there also are no integer-only operators.
MarioDS over 9 years

@Lucero oh, yes that makes sense! Thanks for the insight.
Paul Redmond almost 8 years

Why does 1 % x always return 1? Unless x is less than 1? E.g. 1 % 2 returns 1, why? 1 can't be divided by 2.
Conny Olsson almost 8 years

@Paul Redmond, because you can't fit 2 into 1 (= 0 times). This gives the remainder 1.
Aaron Franke almost 5 years

In C-like languages, including JavaScript, % is the remainder operator, not modulo/modulus. They are equivalent for positive values, but different for negative ones.
Peter over 4 years

downvoting this answer as it doesn't add anything useful to this conversation.
dex10 over 3 years

Thanks! This helped me answer my coding bootcamp's challenge easily.