tips for obtaining the highest value among multiple keys within an array

Question

tips for obtaining the highest value among multiple keys within an array

How can I find the maximum value among multiple keys in an array?

I previously attempted to find the maximum values for just three keys.

getMaxValuefromkeys(values: any[], key1: string, key2: string, key3: string) {
    var val1 = Math.max.apply(Math, values.map(function (a) { return a[key1] }));
    var val2 = Math.max.apply(Math, values.map(function (a) { return a[key2]; }));
    var val3 = Math.max.apply(Math, values.map(function (a) { return a[key2]; }));
    if (val1 >= val2 || val1 >= val3) {
        return val1;
    } else if (val2 >= val3 || val2 >= val1) {
        return val2;
    }
    return val3;
}

However, I realized that using this approach requires more conditions and code when dealing with multiple keys. Thus, I explored the following solution:

Math.max.apply(Math, values.map(function (a) { return a[key1], a[key2], a[key3]; }));
                                         // here I attempt to use multiple keys

Unfortunately, this approach did not work as expected. Is there a single line of code available for finding the maximum value among multiple keys in an array?

javascript angularjs arrays angular typescript

Answer 1

Answer №1

Array#map each element to its highest value, then determine the maximum value in the array:

var values = [{ a: 4, b: 3 }, { a: 2, b: 8 }, { a: 1, b: 2 }];

var key1 = 'a', key2 = 'b';

var result = Math.max.apply(Math, values.map(function (element) { return Math.max(element[key1], element[key2]); }));

console.log(result);

If you require a more versatile solution that can handle multiple keys:

var values = [{ a: 4, b: 3, c: 23 }, { a: 2, b: 28, c: 13 }, { a: 1, b: 2, c: 1 }];

function getMaxOfKeys(values, keys) {
  return Math.max.apply(Math, values.map(e) {
    return Math.max.apply(Math, keys.map(k) {
      return e[k];
    });
  });
}

// or the ES6 equivalent

const getMaxOfKeysES6 = (values, keys) => 
  Math.max(...values.map(
    (e) => 
      Math.max(...keys.map((k) => e[k]))
    )
  );

console.log(getMaxOfKeys(values, ['a', 'b', 'c']));
console.log(getMaxOfKeysES6(values, ['a', 'b', 'c']));

Answer 2

Array#map each element to its highest value, then determine the maximum value in the array:

var values = [{ a: 4, b: 3 }, { a: 2, b: 8 }, { a: 1, b: 2 }];

var key1 = 'a', key2 = 'b';

var result = Math.max.apply(Math, values.map(function (element) { return Math.max(element[key1], element[key2]); }));

console.log(result);

If you require a more versatile solution that can handle multiple keys:

var values = [{ a: 4, b: 3, c: 23 }, { a: 2, b: 28, c: 13 }, { a: 1, b: 2, c: 1 }];

function getMaxOfKeys(values, keys) {
  return Math.max.apply(Math, values.map(e) {
    return Math.max.apply(Math, keys.map(k) {
      return e[k];
    });
  });
}

// or the ES6 equivalent

const getMaxOfKeysES6 = (values, keys) => 
  Math.max(...values.map(
    (e) => 
      Math.max(...keys.map((k) => e[k]))
    )
  );

console.log(getMaxOfKeys(values, ['a', 'b', 'c']));
console.log(getMaxOfKeysES6(values, ['a', 'b', 'c']));

Answer 3

Answer №2

(I prefer plain ES6 over TypeScript)

Suppose you have an object called values and a specific set of keys that you want to compare, like so:

let values = [
   { key1: 2, key2: 3, key3: 0 },
   { key1: 10, key2: 0, key3: 5 }
];

For each key provided, identify the maximum value within each object and return those as an array. Then find the highest value within that array.

function getMaxValuefromkeys(values, ...keys) {
    return Math.max(...keys.map(key => Math.max(...values.map(o => o[key]))));
}

You can implement this function as follows:

let max = getMaxValuefromkeys(values, 'key1', 'key2', 'key3');

Alternatively, if you have an array of keys:

let max = getMaxValuefromkeys(values, ...keys);

Answer 4

(I prefer plain ES6 over TypeScript)

Suppose you have an object called values and a specific set of keys that you want to compare, like so:

let values = [
   { key1: 2, key2: 3, key3: 0 },
   { key1: 10, key2: 0, key3: 5 }
];

For each key provided, identify the maximum value within each object and return those as an array. Then find the highest value within that array.

function getMaxValuefromkeys(values, ...keys) {
    return Math.max(...keys.map(key => Math.max(...values.map(o => o[key]))));
}

You can implement this function as follows:

let max = getMaxValuefromkeys(values, 'key1', 'key2', 'key3');

Alternatively, if you have an array of keys:

let max = getMaxValuefromkeys(values, ...keys);

Answer 5

Answer №3

Using the Math.max method in combination with the map function allows us to find the maximum value between two specific keys in an array of objects.

It's important to note that

return a,b;

The comma operator used here simply returns b.

Answer 6

Using the Math.max method in combination with the map function allows us to find the maximum value between two specific keys in an array of objects.

It's important to note that

return a,b;

The comma operator used here simply returns b.

tips for obtaining the highest value among multiple keys within an array

How can I find the maximum value among multiple keys in an array?

Answer №1

Answer №2

Answer №3

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