movingWindowIndex

movingWindowIndex(X, window, [fixed=false])

X is a vector.

window is an integer no less than 2 indicating the window size.

fixed is a Boolean value, indicating whether the length of each row in the output array vector is fixed to be window. The default value is false. When fixed = true, all rows are of the same length. For the first (window - 1) windows, the indices of missing elements are filled with NULL.

Return an array vector indicating the indices of the elements of X within each sliding window.

S = 1 2 3 4 5 6 7 8 9 0;
m = movingWindowIndex(X=S,window=3);
m;
// output
[[0],[0,1],[0,1,2],[1,2,3],[2,3,4],[3,4,5],[4,5,6],[5,6,7],[6,7,8],[7,8,9]]

mi = movingWindowIndex(X=S,window=3,fixed=true);
mi;
// output
[[,,0],[,0,1],[0,1,2],[1,2,3],[2,3,4],[3,4,5],[4,5,6],[5,6,7],[6,7,8],[7,8,9]]

// obtain the first element from each window
S[m[0]]
// output
[1,1,1,2,3,4,5,6,7,8]

S[mi[0]]
// output
[,,1,2,3,4,5,6,7,8]