What is the javascript equivalent of numpy argsort?
You can use a Schwartzian transform also known as Decorate-Sort-Undecorate (DSU) in python.
DSU:
- Decorate - Use Array#Map to enrich each item in the array with the needed sort data
- Sort - sort using the added data
- Undecorate - extract the sorted data using Array#map again
Demo:
const dsu = (arr1, arr2) => arr1
.map((item, index) => [arr2[index], item]) // add the args to sort by
.sort(([arg1], [arg2]) => arg2 - arg1) // sort by the args
.map(([, item]) => item); // extract the sorted items
const clickCount = [5,2,4,3,1];
const imgUrl = ['1.jpg','2.jpg','3.jpg','4.jpg','5.jpg'];
const result = dsu(imgUrl, clickCount);
console.log(result);thanks to dankal444 for the refactor to the function
For completeness, here's my solution to the actual answer (providing argsort function), by expanding on Ori's answer with DSU.
Since sort is by default taking the first element, so implementing it as DSU is merely adding an index, sorting it, then taking the indices.
let decor = (v, i) => [v, i]; // set index to value
let undecor = a => a[1]; // leave only index
let argsort = arr => arr.map(decor).sort().map(undecor);
clickCount = [5, 2, 4, 3, 1]
imgUrl = ['1.jpg', '2.jpg', '3.jpg', '4.jpg', '5.jpg']
order = argsort(clickCount);
newArray = order.map(i => imgUrl[i])
console.log(newArray);