Sorting arrays inside an array

Question

I need to sort some arrays inside an array.

For example:

let mainArr = [['john', 27, 'teacher'], ['Mary', 17, 'student'], ['Jane', 40, 'police']];

In this case I want to sort it by person's age, so the output would be:

let mainArrSorted = [['Mary', 17, 'student'], ['john', 27, 'teacher'], ['Jane', 40, 'police']];

Any sugestions?

NOTE: I don't want to implement array.sort() method.

Thank you in advance.

looks like you are sorting by the age(assuming that is what number is in each sub array) of each array. you could sort by [i][1] ? — Josh Adams, Nov 05 '18 at 22:18
you could sort it as you would sort an array with single items. — Nina Scholz, Nov 05 '18 at 22:18
You would sort it like you would sort an array of any objects, by their `[1]` property. — Bergi, Nov 05 '18 at 22:21

protoproto · Accepted Answer · 2018-11-05T22:48:40.127

You can use array sort function:

let mainArr = [['john', 27, 'teacher'], ['Mary', 17, 'student'], ['Jane', 40, 'police']];
let mainArrSorted = mainArr.sort((a,b)=>(a[1]-b[1]));
console.log(mainArrSorted);
// mainArrSorted = [['Mary', 17, 'student'], ['john', 27, 'teacher'], ['Jane', 40, 'police']];

To prevent the source array will be sorted follow the destination array, you can use this code:

let mainArr = [['john', 27, 'teacher'], ['Mary', 17, 'student'], ['Jane', 40, 'police']];
let mainArrSorted = mainArr.slice();
mainArrSorted.sort((a,b)=>(a[1]-b[1]));
console.log(mainArrSorted); 
// mainArrSorted = [['Mary', 17, 'student'], ['john', 27, 'teacher'], ['Jane', 40, 'police']];

Or if you don't want array sort, you can use this code:

let mainArr = [['john', 27, 'teacher'], ['Mary', 17, 'student'], ['Jane', 40, 'police']];
let mainArrSorted = mainArr.slice();
for(let i=0;i<mainArrSorted.length-1;i++){
    for(let j=i+1;j<mainArrSorted.length;j++){
        if(mainArrSorted[i][1]>mainArrSorted[j][1]){
            let temp = mainArrSorted[i];
            mainArrSorted[i] = mainArrSorted[j];
            mainArrSorted[j] = temp;
        }
    }
}
console.log(mainArrSorted);

you do realise you've also sorted mainArr - which may not be what is required — Bravo, Nov 05 '18 at 22:21
You should use the builtin-functions (sort), it will quicker than the another function that you made! — protoproto, Nov 05 '18 at 22:33

Sorting arrays inside an array

1 Answers1