elemIndices package:slist

O(n). Extends elemIndex, by returning the indices of all elements equal to the query element, in ascending order.

>>> elemIndices 1 $ slist [1,1,1,2,2,4,5,1,9,1]
Slist {sList = [0,1,2,7,9], sSize = Size 5}

>>> take 5 $ elemIndices 1 $ repeat 1
Slist {sList = [0,1,2,3,4], sSize = Size 5}