Re: How do I use Select[list,condition]?

*To*: mathgroup at smc.vnet.net*Subject*: [mg4528] Re: How do I use Select[list,condition]?*From*: Stephen P Luttrell <luttrell at signal.dra.hmg.gb>*Date*: Wed, 7 Aug 1996 04:17:36 -0400*Organization*: Defence Research Agency, Malvern*Sender*: owner-wri-mathgroup at wolfram.com

Jason Welter wrote: > > I have a list that looks like: > > data = {{1,1,a,4,5,6},{2,1,a,2,3,4},{3,1,a,7,8,9}, > {1,2,b,4,5,6},{2,2,b,2,3,4},{3,2,b,7,8,9}, > {1,3,c,4,5,6},{2,3,c,2,3,4},{3,3,c,7,8,9}} > > and I want to pick out the lists that have a 2 as the second element > of the list. I tried something like: > > data1 = Select[data,data[[#,2]]==2]; > > but this doesn't work. How do I do it? Try the following: data = {{1,1,a,4,5,6},{2,1,a,2,3,4},{3,1,a,7,8,9}, {1,2,b,4,5,6},{2,2,b,2,3,4},{3,2,b,7,8,9}, {1,3,c,4,5,6},{2,3,c,2,3,4},{3,3,c,7,8,9}}; Select[data, MatchQ[#, {_,2,___}]&] which produces the output {{1, 2, b, 4, 5, 6}, {2, 2, b, 2, 3, 4}, {3, 2, b, 7, 8, 9}} -- Dr Stephen P Luttrell luttrell at signal.dra.hmg.gb Adaptive Systems Theory 01684-894046 (phone) Room EX21, Defence Research Agency 01684-894384 (fax) Malvern, Worcs, WR14 3PS, U.K. http://www.dra.hmg.gb/cis5pip/Welcome.html ==== [MESSAGE SEPARATOR] ====