RE: DeleteCases : several at once, conditions
- To: mathgroup at smc.vnet.net
- Subject: [mg49375] RE: [mg49369] DeleteCases : several at once, conditions
- From: "Wolf, Hartmut" <Hartmut.Wolf at t-systems.com>
- Date: Sat, 17 Jul 2004 06:38:38 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
>-----Original Message----- >From: camerzone [mailto:camerzone at yahoo.com] To: mathgroup at smc.vnet.net >Sent: Friday, July 16, 2004 12:07 PM >To: mathgroup at smc.vnet.net >Subject: [mg49375] [mg49369] DeleteCases : several at once, conditions > > >Suppose you have a list of lists, something like >{{1, 6, 7}, {3, 6, 9}, {1, 2, 11}, {3, 5, 9}, {2, 5, 6}, {2, 9, 11}, { > 2, 10, 11}, {3, 7, 9}, {5, 8, 11}, {3, 7, 9}, {7, 8, 9}, {2, 5, 12}, >{2, 6, > 10}, {2, 10, 11}, {1, 6, 9}, {6, 10, 12}, {3, 6, 12}, {2, 5, 12}, >{3, 8, > 9}, {1, 2, 7}} >and you want to delete cases matching several different patterns, say >{1,_,_} and {9,_,_} >What's the most efficient way? > >Also, can you use conditions with DeleteCases? Say, I want to delete >all cases containing even numbers? > >tks > > Read (at Help [Master Index] > Patterns) or try, e.g.: DeleteCases[lis, {1 | 2, _, _}] DeleteCases[lis, {x_, _, _} /; x < 3] DeleteCases[lis, {x_?EvenQ, _, _}] Let's talk about efficiency later. -- hw