On Tue, Oct 02, 2007 at 01:36:02PM +0100, Michael Hoffman wrote: > I am trying to do a type of run-length encoding of a 2D array by axis. I > have an array of values arranged along two axes, state and position. > These are many (180, 30000) uint8 arrays. > > I would like to have a list of tuples like > > (state, start_pos, end_pos, values) > > only separating out a set of values into a new tuple if they are all the > same value in a run of at least 10 cells.
This snippet does run-length encoding for one row. x = N.array([1,1,1,1,1,1,1,1,1,1,0,0,2,2,9,9,9,9,9,9,9,9,9,9]) pos, = N.where(N.diff(x) != 0) pos = N.concatenate(([0],pos+1,[len(x)])) rle = [(a,b,x[a]) for (a,b) in zip(pos[:-1],pos[1:])] [(0, 10, 1), (10, 12, 0), (12, 14, 2), (14, 24, 9)] Maybe you can use that as a starting point. Cheers Stéfan _______________________________________________ Numpy-discussion mailing list [email protected] http://projects.scipy.org/mailman/listinfo/numpy-discussion
