如何在不使用for循环的情况下从JavaScript数组的每个数组中返回两个最大数？

Question

  function theHighest(data) { let twoLargest = data.map((x) => { return x.reduce((prev, curr) => { return curr }) }) return twoLargest //returns [3,5,8] } console.log(theHighest([[1, 2, 3], [3, 4, 5], [6, 7, 8]])) 

The above function can return the largest numbers in each array and if it could return prev along with curr in the same array the job would be done and the desired result would be achieved which is [2,3,4,5,7,8] How can I return this without using for loops at all?

If I use for loops here is how I do it:

  function theHighest(data) { let highestValues = [] for (let i = 0; i < data.length; i++) { let first = 0 let second = 0 for (let j = 0; j < data[i].length; j++) { if (first < data[i][j]) { second = first; first = data[i][j]; } else if (second < data[i][j]) { second = data[i][j]; } } highestValues.push(first, second) } return highestValues } console.log(theHighest([[1, 2, 3], [3, 4, 5], [6, 7, 8]])) 

Thank you!

Answer 1

You could take a copy, sort the array and return the two max values.

 function theHighest(data) { return [].concat(...data.map(a => a.slice().sort((a, b) => a - b).slice(-2))); } console.log(theHighest([[1, 2, 3], [3, 4, 5], [6, 7, 8]])); 

Answer 2

You need to sort the array as well if it not sorted

 function theHighest(data) { let twoLargest = data.map((x) => { // Get two largest integers return x.sort().slice(-2); }) // Flatten the array return Array.prototype.concat(...twoLargest); } console.log(theHighest([[1, 2, 3], [3, 4, 5], [6, 7, 8]])) 

Answer 3

You can also use reduce and sort

var output = arr.reduce( (a, c) => a.concat(c.sort().slice(-2)), [] );

outputs [2,3,4,5,7,8]

Demo

 var arr = [[1, 2, 3], [3, 4, 5], [6, 7, 8]]; var output = arr.reduce( (a, c) => a.concat(c.sort().slice(-2)), [] ); console.log( output );