Guidelines for generating a sorted indices array from a different array using TypeScript

Question

Guidelines for generating a sorted indices array from a different array using TypeScript

I need help finding a way to create an ordered array of indexes from another array in TypeScript.

Let me provide some examples: imagine a function that takes an array of any length and returns another array with the indexes of the elements in ascending order:

Example 1: Input=(5.3, 2.4, 4.5, 6.2) > Output=(1,2,0,3).
Example 2: Input=(10, 11, 5, 34, 3, 7, 17) > Output=(4,2,5,0,1,6,3).

I am unable to use array.sort() as it would alter the original array.

I am struggling with this problem as my experience with JS and TS is limited (I am a Delphi programmer who is a bit rusty).

Any insights or advice would be greatly appreciated. Thank you in advance.

javascript arrays typescript sorting

Answer 1

Answer №1

Utilize the slice() method to create a duplicate array that can be sorted without changing the original, then apply map() to generate an array containing the index of each sorted element in the original array.

const numbers = [5.3, 2.4, 4.5, 6.2],
      numbers2 = [10, 11, 5, 34, 3, 7, 17];

const getSortedIndex = (arr) => {
  return arr.slice().sort((a, b) => a - b).map(n => arr.indexOf(n))
}

console.log(JSON.stringify(getSortedIndex(numbers)));
console.log(JSON.stringify(getSortedIndex(numbers2)));

Answer 2

Utilize the slice() method to create a duplicate array that can be sorted without changing the original, then apply map() to generate an array containing the index of each sorted element in the original array.

const numbers = [5.3, 2.4, 4.5, 6.2],
      numbers2 = [10, 11, 5, 34, 3, 7, 17];

const getSortedIndex = (arr) => {
  return arr.slice().sort((a, b) => a - b).map(n => arr.indexOf(n))
}

console.log(JSON.stringify(getSortedIndex(numbers)));
console.log(JSON.stringify(getSortedIndex(numbers2)));

Answer 3

Answer №2

Is it possible to duplicate the array and then arrange the duplicate in order?

let originalArray = [3,6,1,9,2.5];
let sortedArray = [];
for(let j=0;j<originalArray.length;j++){
  sortedArray.push(originalArray[j]);
}
sortedArray.sort();
//originalArray = [3,6,1,9,2.5]
//sortedArray = [1,2.5,3,6,9]

Answer 4

Is it possible to duplicate the array and then arrange the duplicate in order?

let originalArray = [3,6,1,9,2.5];
let sortedArray = [];
for(let j=0;j<originalArray.length;j++){
  sortedArray.push(originalArray[j]);
}
sortedArray.sort();
//originalArray = [3,6,1,9,2.5]
//sortedArray = [1,2.5,3,6,9]

Answer 5

Answer №3

It only takes two simple lines of code to achieve this:

const unsorted = [10, 20, 5, 8, 3];
const sorted = unsorted.slice().sort();

console.log(sorted);      // [3, 5, 8, 10, 20]
console.log(unsorted);    // [10, 20, 5, 8, 3]

Answer 6

It only takes two simple lines of code to achieve this:

const unsorted = [10, 20, 5, 8, 3];
const sorted = unsorted.slice().sort();

console.log(sorted);      // [3, 5, 8, 10, 20]
console.log(unsorted);    // [10, 20, 5, 8, 3]

Guidelines for generating a sorted indices array from a different array using TypeScript

Answer №1

Answer №2

Answer №3

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