Getting the max value from an array within an array

Question

Just starting to learn Javascript and Angular. I have an array within an array.

This is my array structure:

[[object1, object2],[object3, object 4]];

I want to get the highest value from object2 and object 4.

When i only had one array i used

Math.max.apply(Math, array.map(function(o){return o.collectionID;}));

Is it possible and how can i retrieve the highest value from an array within an array?

apply it to `parentArray[n]`? – Jeremy Thille Mar 24 '17 at 10:50 — Jeremy Thille, Mar 24 '17 at 10:50
Can you post your array structure? – Jatin patil Mar 24 '17 at 10:51 — Jatin patil, Mar 24 '17 at 10:51

score 0 · Answer 1 · edited May 23 '17 at 11:54

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Here is the very simple and powerful answer [https://stackoverflow.com/a/23397247/3455035]

edited May 23 '17 at 11:54

Community

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answered Mar 24 '17 at 10:55

anoop

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Nina Scholz · Accepted Answer · 2017-03-24T11:30:46.783

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You could collect all id with Array#reduce for any depth arrays.

Then take only collectionID where it is set.

var array = [[{}, { collectionID: 1 }], [{}, { collectionID: 2 }], [{}, { collectionID: 3 }], [{ collectionID: 42 }, { collectionID: 4 }]],
    max = Math.max.apply(Math, array.reduce(function iter(r, a) {
        return r.concat(Array.isArray(a) ? a.reduce(iter, []) : 'collectionID' in a ? a.collectionID : []);
    }, []));
    
console.log(max);

edited Mar 24 '17 at 11:30

answered Mar 24 '17 at 10:57

Nina Scholz

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Thanks for the fast response! My array format is [[{object},{collectionID: 1}],[{object},{collectionID: 2}]] How could i choose the second object in the array? – Urban Mar 24 '17 at 11:11
I mean the collectionID object isn't always the second of the array. – Urban Mar 24 '17 at 11:17
Thank you very much! Really helped me a lot. – Urban Mar 24 '17 at 11:30

Getting the max value from an array within an array

2 Answers2