CODEWITHSUNDEEP
javascriptd3.js
Juan Odriozola
Juan Odriozola

Reputation: 45

Maximum value of the second column of an array

Ok my problem is that I loaded this json file in a script. I am also using d3.js

[{"name":"object1","income":[[2013,100], [2014, 450], [2015,175]]}, {"name":"object2","income":[[2013,230], [2014, 250], [2015,375]]}]

The income array is composed of a year and the income value. [2013,100] implies that the income was equal to 100 in 2013. My problem is that I want to obtain the maximum value of the income of the dataset. In this case the maximum is equal to 450. Is it possible to do this with the d3.max function

Thanks a lot.

Upvotes: 0

Views: 437

Answers (4)

Nina Scholz
Nina Scholz

Reputation: 386670

A solution, the question was for me unclear, get the max income for every year, or the max income from all years.

var data = [{ "name": "object1", "income": [[2013, 100], [2014, 450], [2015, 175]] }, { "name": "object2", "income": [[2013, 230], [2014, 250], [2015, 375]] }],

    // max gouped by year
    max = data.reduce(function (max, o) {
        o.income.forEach(function (a) {
            max[a[0]] = Math.max(max[a[0]] || a[1], a[1]);
        });
        return max;
    }, {}),

    // single value taken from the year object
    maxTotal = Object.keys(max).reduce(function (m, k) {
        return Math.max(m, max[k]);
    }, Number.MIN_VALUE),

    // single run max from all objects and years
    maxAll = data.reduce(function (m, o) {
        return o.income.reduce(function (mm, a) {
            return Math.max(mm, a[1]);
        }, m);
    }, Number.MIN_VALUE);

console.log('max', max);
console.log('maxTotal', maxTotal);
console.log('maxAll', maxAll);

Upvotes: 0

Lars Kotthoff
Lars Kotthoff

Reputation: 109242

Yes you can do this quite easily with D3, using the second argument to d3.max which takes an element and returns the part of it to take the max of:

var maxIncome = d3.max(data, function(d) {
    return d3.max(d.income, function(e) { return e[1]; });
});

Upvotes: 2

Arun P Johny
Arun P Johny

Reputation: 388396

In modern browsers

var data = [{
  "name": "object1",
  "income": [
    [2013, 100],
    [2014, 450],
    [2015, 175]
  ]
}, {
  "name": "object2",
  "income": [
    [2013, 230],
    [2014, 250],
    [2015, 375]
  ]
}];

var max = Math.max.apply(Math, data.map(function(item) {
  return item.income.reduce(function(a, b) {
    return a > b[1] ? a : b[1]
  }, 0)
}));
snippet.log(max)
<!-- Provides the `snippet` object, see http://meta.stackexchange.com/a/242144/134069 -->
<script src="http://tjcrowder.github.io/simple-snippets-console/snippet.js"></script>

Upvotes: 1

user405398
user405398

Reputation:

How about plain old javascript;

var max = 0;
var dataset = [{"name":"object1","income":[[2013,100], [2014, 450], [2015,175]]}, {"name":"object2","income":[[2013,230], [2014, 250], [2015,375]]}];
dataset.forEach(function(obj) {
  obj.income.forEach(function(arr) {
    var val = arr[1];
    if(val > max) {
      max = val;
    }
  });
});
console.log(max);

Upvotes: 2

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