array return index from another array

Question

suppose we have this two array. in some condition, I want to return the index of a second array.

let a = [1, 2 ,3 ,4 ,5 ,6 ,7 ,8 ,9 ,10 ,11 , 12]
let b = [0, 1, 2, 3 , 4 , 5, 6 , 7 , 8, 9, 10, 11]

if (a[2]) ? return b[2] : return null

why I need this? because I have a month number of the year that starts from 0 to 11. but I need to turn this 1 12 for storing in my database. sry about the title of this question if someone has a better title I would be glad about changing it.

The question is a bit unclear, at least to me. Can you please edit your question and add the expected output? — Mureinik
– Mureinik, Commented Jun 1, 2019 at 17:15
What does the duration have to do with anything? If you are just getting the month from 1 you literally just do b[i] + 1. Doesn't matter how many years its for? — basic
– basic, Commented Jun 1, 2019 at 17:20

Nina Scholz · Accepted Answer · 2019-06-01 17:21:14Z

3

You could calculate the value by adding 11 and get the remainder value with 12.

function getZeroBasedMonth(n) {
    return (n + 11) % 12;
}

console.log(getZeroBasedMonth(1));
console.log(getZeroBasedMonth(12));

For the getting the opposite, just add one.

function getMonth(n) {
    return n + 1;
}

console.log(getMonth(0));
console.log(getMonth(11));

edited Jun 1, 2019 at 17:21

answered Jun 1, 2019 at 17:15

Nina Scholz

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1 Comment

Babak Abadkheir Over a year ago

tnx but I need the opposite of this condition , sry if im not clear about that. console.log(getZeroBasedMonth(0)) >>> 1 and console.log(getZeroBasedMonth(11)) >>> 12

basic · Accepted Answer · 2019-06-01 17:23:15Z

0

Why make this harder than it needs to be? Just add 1 to the value you get from your initial array. Here is, per your comment, 10 years worth of values for the months with a +1 value.

let years = 10;
let months = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11];
let allYears = [];

for(let i = 0; i < years; i++){
    let year = [];
    for(let x = 0; x < months.length; x++){
        year[x] = months[x] + 1;
    }
    allYears.push(year);
}

console.log(allYears);

answered Jun 1, 2019 at 17:23

basic

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1 Comment

willy1994 Over a year ago

if you decide to go down this path, Javascript has a map function for this. There is no need to di it with for loops.

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