CODEWITHSUNDEEP
javascriptarraysmultidimensional-array
provola
provola

Reputation: 352

Max value of a multidimensional array javascript

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]]

Upvotes: 11

Views: 31722

Answers (10)

Tyron
Tyron

Reputation: 1966

I found this way to your solution very simple way

function largestOfFour(arr) {
  let maxValue;
  let arrMax = []
for(let i = 0 ; i < arr.length ; i++){
maxValue = Math.max.apply(null ,arr[i])
arrMax.push(maxValue)
}
  return arrMax;
}
largestOfFour([[4, 5, 1, 3], [13, 27, 18, 26], [32, 35, 37, 39], [1000, 1001, 857, 1]]);
 return --> [ 5, 27, 39, 1001 ]

Upvotes: 0

Vikram Deshmukh
Vikram Deshmukh

Reputation: 15616

Simplest Solution

Flatten and use the usual Math.max with spread operator.

Math.max(...arr.flat())

const 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]];

Math.max(...arr.flat())

Upvotes: 8

Exo Flame
Exo Flame

Reputation: 147

If i could i would comment this on DankMasterDan's answer

let a = [[12,45,75], [54,45,2],[23,54,75,2]];
let max = Math.max(...a.map(r=>Math.max(...r)));

this may avoid the stack size exceeded error. David mentioned since its is batching each row with the map first.

Upvotes: 0

DankMasterDan
DankMasterDan

Reputation: 2123

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);

Upvotes: 1

Pani
Pani

Reputation: 1377

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);

Upvotes: 13

Rafi
Rafi

Reputation: 824

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));

Upvotes: 4

Redu
Redu

Reputation: 26161

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));

Upvotes: 8

Olli K
Olli K

Reputation: 1760

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;
}, {});

Upvotes: 0

RomanPerekhrest
RomanPerekhrest

Reputation: 92854

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

Upvotes: 0

Umair Malik
Umair Malik

Reputation: 1451

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().

Upvotes: 5

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