Oh shoot. I used array = [array, other_array].flatten to get around the += slowness. Way faster on lists of tens of thsouands that I was throwing around. Totall

Oh shoot. I used array = [array, other_array].flatten to get around the += slowness. Way faster on lists of tens of thsouands that I was throwing around. Totally forgot push. (Granted, my solution was developed on Sunday morning with a hard deadline of Monday morning and I had been working hard all week. )