I have this particular array of floats
segm3 = [0.0, 2.5, 3.62, 0.0, 2.5, 3.62, 0.0]
I desire to sort it while keeping the original indexes. This is my code:
var indices = Array.from(Array(segm3.length).keys())
.sort(function(a,b) { if (segm3[a] > segm3[b]) return 1;
else if (segm3[a]<segm3[b]) return -1 ;else return 0;})
when I try to console.log the indexes I get this
[
0, 3, 6, 1,
4, 2, 5
]
It should be right, but after I sort segm3 how can I return back to form the original segm3 with the use of the indexes list ?
To keep the original indexes you can use Array.prototype.map() and Array.prototype.sort():
Code:
const segm3 = [0.0, 2.5, 3.62, 0.0, 2.5, 3.62, 0.0]
const segm3SortedWithIndexes = segm3
.map((f, i) => ({
floatNumber: f,
index: i, // <-- original index
}))
.sort((a, b) => a.floatNumber - b.floatNumber)
console.log('"segm3" with original index:', segm3SortedWithIndexes)
const result = segm3SortedWithIndexes.map(({ floatNumber: f }) => f)
console.log('"segm3" sorted:', result)after segm3.sort(function(a,b) {return a-b})
just
let resultArr;
for(var i=0;i<indices.length;i++){
resultArr[indices[i]]=segm3[i]
}
It was simple as that but my mind was melt
Having got the indices sorted according to the values in segm3, if you then sort segm3 you can then restore the original ordering of segm3 by using the indices array to extract the values from the sorted segm3 array:
const segm3 = [0.0, 2.5, 3.62, 0.0, 2.5, 3.62, 0.0]
console.log(JSON.stringify(segm3))
let indices = Array.from(Array(segm3.length).keys())
.sort((a,b) => segm3[a] - segm3[b])
console.log(JSON.stringify(indices))
segm3.sort((a,b) => a - b);
console.log(JSON.stringify(segm3))
let origsegm3 = indices.map(i => segm3[i])
console.log(JSON.stringify(origsegm3))