Return Maximum value from a JSON Object

Question

I have an associative array which looks like:

var data = { 0: { 'Number_of_Something': 212 }, 1: { 'Number_of_Something': 65 }, 2: { 'Number_of_Something': 657 } }

I need to extract the highest value in the field Number_of_Something, however, because it is a field within an object of an object, it is a little more complicated than just following a similar method to something outlined here.

Looping through the object and storing the value, then replacing it if the next one is larger seems like the easiest and obvious option.

I am simply asking this question in case there is a simpler (smarter) way of achieving this other than the method outlined above?

Why is data an object and not an array or at least array-like object? — Felix Kling
– Felix Kling, Commented Apr 15, 2013 at 11:09
@FelixKling it is a JSON object passed from a PHP script. I force an object for other purposes :) — Ben Carey
– Ben Carey, Commented Apr 15, 2013 at 11:17
What is wrong with looping over the object members? That seems pretty simple, maintainable and very compatible to me. — RobG
– RobG, Commented Apr 15, 2013 at 11:22
@RobG Absolutely nothing wrong with it, but I just wanted to check there were not any javascript functions already there that would make the process simpler :-) — Ben Carey
– Ben Carey, Commented Apr 15, 2013 at 11:23
I don't see how nesting 3 functions is simpler that basic loop. A little less code perhaps, but certainly not simpler. Performance seems mixed, it doesn't seem any faster on balance. — RobG
– RobG, Commented Apr 15, 2013 at 11:38

Cattode · Accepted Answer · 2013-04-15 11:18:31Z

simpler can be subjective... Another way to achieve what you ask is to get an array of the values using Object.keys and Array.prototype.map, and use the other solution with Math.max that you linked :

var data = { 0: { 'Number_of_Something': 212 }, 1: { 'Number_of_Something': 65 }, 2: { 'Number_of_Something': 657 } } var max = Math.max.apply(null, Object.keys(data).map(function(e) { return data[e]['Number_of_Something']; }));

It will need shims for missing ES5 features like Object.keys and map.
How can I return the index of the item with the highest number?

Bas Slagter · Accepted Answer · 2013-04-15 11:10:03Z

0

You can create your own (for) loop and return the max value that way. Another option is to use a library like Underscore.js to handle this for you and keep your code readable.

answered Apr 15, 2013 at 11:10

Bas Slagter

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3 Comments

Ben Carey Over a year ago

Okay, thank you. So, in short, without a plugin there is no short easy way, I need to loop through as I suggested in my question?

Bas Slagter Over a year ago

Well...a plugin will also loop through the object/array internally. There is no other solution.

Ben Carey Over a year ago

Thought so :-). I have accepted @Zapshu's solution as it provides exactly what I am looking for. Thanks anyway

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