Re: List Operations
- To: mathgroup at smc.vnet.net
- Subject: [mg65688] Re: List Operations
- From: bghiggins at ucdavis.edu
- Date: Sun, 16 Apr 2006 01:44:45 -0400 (EDT)
- References: <e1nn6s$lmm$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Try this: mylist = {{1, a, b1, c1}, {1, a, b2, c2, c3}, {1, a, b3, c4}, {2, b, z1}, {2, b, z2, c3}, {2, b, z3, c4, c5}, {2, b, z4}, {3, x, y1, c1, c5}, {3, x, y2, c3, c2}, {3, x, y3, c1}, {3, x, y4, c3, c1, c2}} I have made the sublists of different length Map[{#, Apply[Plus, Cases[mylist, {#, x_, y_, ___} -> x y]]} &, {1, 2, 3}] {{1, a b1 + a b2 + a b3}, {2, b z1 + b z2 + b z3 +b z4}, {3, x y1 + x y2 + x y3 + x y4}} Hope this helps, Cheers, Brian