Get Max Key in Key-Value Pair in JavaScript

Question

Please consider these Key-Value Pairs:

var dict_Numbers = {"96": "0",
                    "97": "1",
                    "98": "2",
                    "99": "1",
                    "100": "4",
                    "101": "0"}

I would like to get the highest value - in this example it would be 101.

How can I achieve this?

Thanks

Update 1:

I use this code: Fast way to get the min/max values among properties of object and Getting key with the highest value from object

but both return Max Value from string comparator

With 4k rep you should know to write a [mcve] showing what you have tried. It is really not difficult to find examples here - Math.max and Object.keys — mplungjan, Dec 28 '16 at 08:40
Possible duplicate of [Getting key with the highest value from object](http://stackoverflow.com/questions/27376295/getting-key-with-the-highest-value-from-object) except that you've to use `parseInt` to convert the string to an integer. — Arun Kumar Mohan, Dec 28 '16 at 08:42
Can't you figure out how to compare keys instead of values from the answer I linked? See @mplungjan's answer. He has exactly done that. — Arun Kumar Mohan, Dec 28 '16 at 08:47
look at this [example]: http://stackoverflow.com/questions/1669190/javascript-min-max-array-values — MKAD, Dec 28 '16 at 08:49

score 14 · Answer 1 · edited Dec 28 '16 at 08:50

14

Nice example from MDN:

var dict_Numbers = {"96": "0",
                    "97": "1",
                    "98": "2",
                    "99": "3",
                    "100": "4",
                    "101": "5"}
                    
                    
function getMax(obj) {
  return Math.max.apply(null,Object.keys(obj));
}
console.log(getMax(dict_Numbers));

edited Dec 28 '16 at 08:50

mplungjan

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answered Dec 28 '16 at 08:47

sinisake

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Like I thought. I took the duplicate suggestion instead in my answer :) – mplungjan Dec 28 '16 at 08:49
[5 years later](https://stackoverflow.com/a/41358362/295783): `const max = Math.max(...Object.keys(dict_Numbers))` – mplungjan Feb 11 '21 at 19:23

mplungjan · Answer 2 · 2021-02-11T19:21:45.900

Applying to the keys the easily found Getting key with the highest value from object paying attention to the strings

const dict_Numbers = {
    "96": "0",
    "97": "1",
    "08": "8", // just to make sure
    "09": "9", // just to make sure
    "98": "2",
    "99": "3",
    "100": "4",
    "101": "5"
  },
  max = Object.keys(dict_Numbers)
  .reduce((a, b) => +a > +b ? +a : +b)
console.log(max)

But as I commented on the question, there is a neater way using Math.max on the Object.keys

Now even more elegant using spread

const dict_Numbers = {
    "96": "0",
    "97": "1",
    "08": "8", // just to make sure
    "09": "9", // just to make sure
    "98": "2",
    "99": "3",
    "100": "4",
    "101": "5"
  },
  max = Math.max(...Object.keys(dict_Numbers))
console.log(max)

Sinisake's answer is good, but seems to only work if the keys are numeric, yours works with all keys. — Alex Collette, Feb 11 '21 at 18:53

str · Answer 3 · 2016-12-28T09:01:51.283

4

var dict_Numbers = {"96": "0",
                    "97": "1",
                    "98": "2",
                    "99": "3",
                    "100": "4",
                    "101": "5"}

console.log(Math.max(...Object.keys(dict_Numbers)));

Note that this code uses ES6 features.

edited Dec 28 '16 at 09:01

answered Dec 28 '16 at 08:48

str

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Cool but the `return Math.max.apply(null,Object.keys(obj));` is by far easier on the eye and brain – mplungjan Dec 28 '16 at 08:59
@mplungjan Actually, I think it is the other way around :) – str Dec 28 '16 at 09:02
1

I just removed the explicit `parseInt` because `Math.max` already does it. But in my opinion, reading the spread operator is easier than `.bind` anyway. – str Dec 28 '16 at 09:05
Using a transpiler should be standard practice by now :) – str Dec 28 '16 at 09:17

score 1 · Accepted Answer · edited Dec 28 '16 at 12:10

1

Try this.

You can iterate over the properties of the object and check for its value.

var dict_Numbers = {
  "96": "0",
  "97": "1",
  "98": "2",
  "99": "3",
  "100": "4",
  "101": "5"
};

var max = 0;

for (var property in dict_Numbers) {
  max = (max < parseFloat(property)) ? parseFloat(property) : max;
}

console.log(max);

edited Dec 28 '16 at 12:10

Arian

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answered Dec 28 '16 at 08:46

Deep

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1

Seriously @Arian, that is the answer you went with? At least add the radix to the parseInt or you will have fun with 08 and 09 – mplungjan Dec 28 '16 at 09:00
@mplungjan , dont yo think providing a default value is overkill, by default radix is 10 for parseInt() . May be i am wrong but it looks straightforward overkill but i do like sinisake's answer though – Deep Dec 28 '16 at 09:01
Right - so they fixed that. It used to give surprises with the invalid octal values 08 and 09 – mplungjan Dec 28 '16 at 09:06
yeah but that will affect if try to parseInt a digit i.e. parseInt(015) which results 13 but with strings i.e. parseInt("015") it will not matter. – Deep Dec 28 '16 at 09:16
@Arian - why change to parseFloat? Will there be decimals in your "keys" ? – mplungjan Dec 29 '16 at 07:03

score 0 · Answer 5 · edited Dec 28 '16 at 08:54

0

var dict_Numbers = {
    "96": "0",
    "97": "1",
    "98": "2",
    "99": "3",
    "100": "4",
    "101": "5"
  },
  key,
  intKey,
  maxKey = 0;

for (key in dict_Numbers) {
  intKey = parseInt(key);
  if (intKey > maxKey) {
    maxKey = intKey;
  }
}
console.log(maxKey);

edited Dec 28 '16 at 08:54

mplungjan

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answered Dec 28 '16 at 08:54

Aditya Singh

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Get Max Key in Key-Value Pair in JavaScript

5 Answers5