opposite of partition

*To*: mathgroup at smc.vnet.net*Subject*: [mg57539] opposite of partition*From*: Guy Israeli <guyi1 at netvision.net.il>*Date*: Tue, 31 May 2005 05:00:45 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

Hi, How do I do the opposite of partition quickly? for example: l1= {{a, b, c, d, e}, {f, g, h, i, j}, {k, l, m, n, o}, {p, q, r, s, t}, {u, v, w, x, y}} and then if I partition it to blocks will result in {{{{a, b}, {f, g}}, {{c, d}, {h, i}}}, {{{k, l}, {p, q}}, {{m, n}, {r, s}}}} flattening it won't help, and its messy to do it by taking all first lines of the blocks, then second.. How can I do it quickly? Thanks, Guy