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.         


        

Answer 1

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;
}, {});

Answer 2

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);

Answer 3

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));

Answer 4

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

Answer 5

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);

Answer 6

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().