sortIndices function

float[] sortIndices(array)

array float[]string[] Array to be sorted.

Returns the indices of sorted values in array.

Basic sorting

array =                                          ["c","b","d","a"]
sortIndices(array)                               [3,1,0,2]
array[sortIndices(array)]                        ["a","b","c","d"]

Duplicate values are sorted in the order of appearance.

array =                                          [2,1,3,3,1]
sortIndices(array)                               [1,4,0,2,3]
array[sortIndices(array)]                        [1,1,2,3,3]

Each row is sorted separately. The returned index array has the same dimensions as array.

array =                                          ["e","c","d";
                                                  "b","a","c";
                                                  "d","a","d"]

sortIndices(array) =                             [1,2,0;
                                                  4,3,5;
                                                  7,6,8]

array[sortIndices(array)] =                      ["c","d","e";
                                                  "a","b","c";
                                                  "a","d","d"]

Related

Array types operators findFirstfunction sortRowIndicesfunction

Examples

Ascending and descending sorting

reverse(array) = array[size(array)-1:-1:0]

sortAsc(array) = array[sortIndices(array)]
sortDesc(array) = reverse(sortAsc(array))

const a = ["a", "c", "b"]
const b = sortAsc(a)       // [a,b,c]
const c = sortDesc(a)      // [c,b,a]

An array is indexed with sorted indices which sorts all values in ascending order. The resulting array can be reversed for a descending sort order. This example only applies to 1D arrays with one row.

Finding minimum and maximum

findMin(array) = sortIndices(array)[0]
findMax(array) = sortIndices(array)[size(array)-1]

min(array) = array[findMin(array)]
max(array) = array[findMax(array)]

const a = [1, 4, -1, 9]
const b = min(a)           // -1
const c = max(a)           // 9

The index of the minimum value in array is the first element in the sorted index array. For 2D arrays, flatten first:

flatten(array) = array[0:size(array)-1]

findMin(array) = sortIndices(flatten(array))[0]
findMax(array) = sortIndices(flatten(array))[size(array)-1]