Max value of a multidimensional array javascript

Question

I have a multidimensional array of x columns and y rows. How can I find the min and the max value of the matrix? Example:

[[1,  37.8, 80.8, 41.8],
[2,  30.9, 69.5, 32.4],
[3,  25.4,   57, 25.7],
[4,  11.7, 18.8, 10.5],
[5,  11.9, 17.6, 10.4],
[6,   8.8, 13.6,  7.7],
[7,   7.6, 12.3,  9.6],
[8,  12.3, 29.2, 10.6],
[9,  16.9, 42.9, 14.8],
[10, 12.8, 30.9, 11.6],
[11,  5.3,  7.9,  4.7],
[12,  6.6,  8.4,  5.2],
[13,  4.8,  6.3,  3.6],
[14,  4.2,  6.2,  3.4]]

put whole code , that you tried, if you have not tried, no one is there to do work for you. — yash, Sep 06 '16 at 07:08
Possible duplicate of [Get largest value in multi-dimensional array javascript or coffeescript](http://stackoverflow.com/questions/11149843/get-largest-value-in-multi-dimensional-array-javascript-or-coffeescript) — Shailendra Sharma, Sep 06 '16 at 07:11
Please share the exact example of multidimensional array. This is not a proper multidimensional array — brk, Sep 06 '16 at 07:15

Pani · Accepted Answer · 2019-08-04T09:05:09.590

7

let

var arr = [[2,3], [4,5]]; // a multidimensional array

then get an array with each row's maximum with

var maxRow = arr.map(function(row){ return Math.max.apply(Math, row); });

and the overal maximum with

var max = Math.max.apply(null, maxRow);

edited Aug 04 '19 at 09:05

answered Sep 06 '16 at 07:25

Pani

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How would you get max of every column or of say columns 2-5? – Ramin Melikov Oct 05 '20 at 03:54

score 5 · Answer 2 · answered Sep 06 '16 at 07:16

5

You can get max value of multi dimension array using following method:

var arr = [[1, 5,6], [4, 7,8], [3, 8,20], [2, 3,1],[12, 4,5]];

console.log(Math.max.apply(Math, arr.map(function (i) {
    return i[0]+i[1]+i[2];
})));

It first use array.map() to convert the multi-dimensional array to a flat one, and after that use Math.max().

answered Sep 06 '16 at 07:16

Umair Malik

1,195
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1

Any reason for down voting this answer? – Umair Malik Sep 06 '16 at 07:19

score 5 · Answer 3 · answered Sep 06 '16 at 08:12

Regardless of the dimension of the array, i believe this is the way to get the max of all primitives involved.

function getMax(a){
  return Math.max(...a.map(e => Array.isArray(e) ? getMax(e) : e));
}

var arr = [[1,  37.8, 80.8, 41.8],
           [2,  30.9, 69.5, 32.4],
           [3,  25.4,   57, 25.7],
           [4,  11.7, 18.8, 10.5],
           [5,  11.9, 17.6, 10.4],
           [6,   8.8, 13.6,  7.7],
           [7,   7.6, 12.3,  9.6],
           [8,  12.3, 29.2, 10.6],
           [9,  16.9, 42.9, 14.8],
           [10, 12.8, 30.9, 11.6],
           [11,  5.3,  7.9,  4.7],
           [12,  6.6,  8.4,  5.2],
           [13,  4.8,  6.3,  3.6],
           [14,  4.2,  6.2,  3.4]];
 console.log(getMax(arr));

It should work on arrays with indefinite dimension.

function getMax(a){
  return Math.max(...a.map(e => Array.isArray(e) ? getMax(e) : e));
}

var arr = [[1,  37.8, 80.8, 41.8],
           [2,  30.9, 69.5, 32.4],
           [3,  25.4,   57, 25.7],
           [4,  11.7, 18.8, 10.5],
           [5,  11.9, 17.6, 10.4],
           [6,   8.8, 13.6,  7.7],
           [7,   7.6, 12.3,  9.6],
           [8,  12.3, 29.2, 10.6],
           [9,  16.9, 42.9, 14.8],
           [10, 12.8, 30.9, 11.6],
           [11,  5.3,  [6.1,[56.7,[98.55]]],  4.7],
           [12,  6.6,  8.4,  5.2],
           [13,  4.8,  6.3,  3.6],
           [14,  4.2,  6.2,  3.4]];
 console.log(getMax(arr));

Rafi · Answer 4 · 2018-02-25T09:35:36.417

4

Most answers here use apply or the spread operator ... to call the Math.max function with all the elements of an array as parameters.

For large arrays it is safer to use reduce:

// returns maximum of an array
const getArrayMax = array => array.reduce((a, b) => Math.max(a, b));

// returns maximum of a 2D array
const getArrayMax2d = array2d => getArrayMax(array2d.map(getArrayMax));

edited Feb 25 '18 at 09:35

answered Feb 05 '18 at 09:50

Rafi

627
8
16

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You can do ```getArrayMax(array2d.map(getArrayMax));``` instead of ```getArrayMax(array2d.map(row => getArrayMax(row)));``` – dll Feb 22 '18 at 15:51

score 0 · Answer 5 · answered Sep 06 '16 at 07:19

The solution using Array.prototype.push, Math.min and Math.max methods:

// arr is your initial array
var flattened = [], minValue, maxValue;
arr.forEach(function (v) {
    Array.prototype.push.apply(flattened, v);
});

minValue = Math.min.apply(null, flattened);
maxValue = Math.max.apply(null, flattened);

console.log('min: ' + minValue, 'max: ' + maxValue);  // min: 1 max: 80.8

DEMO link

score 0 · Answer 6 · answered Sep 06 '16 at 07:25

You can also achieve this with a reduction (it's slower but if the array is not huge, it doesn't matter) resulting in a object containing both the min and the max like so:

matrix.reduce(function (res, item) {
    item.forEach(function (val) {
        if (!res.hasOwnProperty('max') || val > res.max) res.max = val;
        if (!res.hasOwnProperty('min') || val < res.min) res.min = val;
    });
    return res;
}, {});

score 0 · Answer 7 · answered Nov 27 '19 at 20:36

0

based on this answer, you can do it in 1 line (assuming ES6):

const arr = [[12,45,75], [54,45,2],[23,54,75,2]];

const max = Math.max(...[].concat(...arr));

const min = Math.min(...[].concat(...arr));

console.log(max);

console.log(min);

answered Nov 27 '19 at 20:36

DankMasterDan

1,353
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this causes a stack size exceeded error. – David Jan 13 '21 at 13:03

Max value of a multidimensional array javascript

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