Re: help with lists operations
- To: mathgroup at smc.vnet.net
- Subject: [mg67845] Re: help with lists operations
- From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
- Date: Mon, 10 Jul 2006 06:38:02 -0400 (EDT)
- References: <e8qgac$o6e$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Hi, I'm not sure, that I understand you right but myCompare[any_, lst : {{_, _} ..}] := myCompare[any, #] & /@ lst; myCompare[{a_, b_}, {a_, c_}] := Sow[b*c]; myCompare[{a_, b_}, {c_, d_}] := Null; Plus @@ Reap[myCompare[#, f2] & /@ f1][[2, 1]] may help. Regards Jens omk wrote: > Hi ALL, > I am a novice in Mathematica, know that there are no easy ways for learning, so spent 2 weeks trying to solve an easy problem, but so far have only ugly solutions. > Yes, I read and reread the Book as well as searched for similar problems on the Forum. > I have 2 lists: > f1={{2, 1}, {3, 1}, {7, 2}, {9, 1}, {10, 1}, {12, 1}, {14, 3}, {19, > 3}, {23, 1}, {24, 1}, {25, 1}} > f2={{2, 2}, {5, 1}, { > 6, 2}, {10, 1}, {14, 3}, {16, 1}, {18, 1}, {21, 3}, {22, 1}, {26, 1}} > I need to compare sublists (pairs) from the first list f1 with pairs from f2. > If pairs with 2 first equal numbers exist, I have to multiply the second, after having products for all such pairs, I need to receive their sum. > Say from f1 and f2 I have {2,1} and {2,2}, the product is 1 2=2, similar {10,1} and {10,1},{14,3} and {14,3}, > so it should be 2+1+9=12 > Any ideas are very welcome > TIA, > omk >