Getting the min and max value in JavaScript, but from a 2D array

Question

I know this gets asked again and again but hear me out - this question is slightly different.

I can get a max or min from a 1D array like this:

var          


        

Answer 1

I really admired the sleek readability of @TedHopp 's solution -- so much so that I decided to adapt it into a function. The practicality of the function is still yet to be seen, but I liked the idea of being able to identify the min / max of a specified index within a 2D array.

function getMinMaxOf2DIndex (arr, idx) {
    return {
        min: Math.min.apply(null, arr.map(function (e) { return e[idx]})),
        max: Math.max.apply(null, arr.map(function (e) { return e[idx]}))
    }
} 

getMinMaxOf2DIndex() takes two parameters, arr -- an array, and idx the index of the values to compare.

Usage Examples:

// using the OP's array as an example
var array = [[1, 112.0],[2,5.12],[3,113.1],[4,33.6],[5,85.9],[6,219.9]];

getMinMaxOf2DIndex(array, 0); // {min: 1, max: 6}
getMinMaxOf2DIndex(array, 1); // {min: 5.12, max: 219.9}

// and so on...
var array = [[1, 9, 6 , 3], [2, 4, 7, 2], [6, 5, 9, 4]];
getMinMaxOf2DIndex(array, 2); // {min: 1, max: 6}
getMinMaxOf2DIndex(array, 3); // {min: 6, max: 9}