RE: more with lists
- To: mathgroup at smc.vnet.net
- Subject: [mg40343] RE: [mg40326] more with lists
- From: "Wolf, Hartmut" <Hartmut.Wolf at t-systems.com>
- Date: Wed, 2 Apr 2003 04:35:46 -0500 (EST)
- Sender: owner-wri-mathgroup at wolfram.com
>-----Original Message----- >From: Nathan Moore [mailto:nmoore at physics.umn.edu] To: mathgroup at smc.vnet.net >Sent: Tuesday, April 01, 2003 11:53 AM >To: mathgroup at smc.vnet.net >Subject: [mg40343] [mg40326] more with lists > > >The replies have been beautiful! > >suppose I have a list of n {x,y}pairs. I'd like to cull the >list into a >smaller list for which the condition x<Xo, y>Yo is true. If >the list was >1-D I could simply use "Select," how do I access the data >points in pairs? > >Nathan Moore >Universoty of Minnesota Physics > > Still use Select! In[29]:= ll = Table[{Random[], i*.1 + Random[]}, {i, 25}] Out[29]= {{0.729666, 0.704118}, {0.623234, 0.349074}, {0.81287, 1.18585}, {0.626257, 0.649148}, {0.668199, 0.879212}, {0.461906, 1.28604}, {0.413234, 1.34433}, {0.719861, 0.920554}, {0.460918, 1.35331}, {0.773022, 1.02309}, {0.502923, 1.36225}, {0.759855, 2.08335}, {0.773257, 1.95813}, {0.136621, 2.13427}, {0.960387, 2.27228}, {0.510364, 2.08513}, {0.292188, 2.09307}, {0.0484584, 2.59908}, {0.878954, 2.64874}, {0.328597, 2.67853}, {0.418037, 2.39543}, {0.555575, 2.85544}, {0.915114, 2.33318}, {0.79572, 3.17209}, {0.141857, 2.87505}} In[30]:= Select[ll, #[[1]] < .7 && #[[2]] > 1. &] Out[30]= {{0.461906, 1.28604}, {0.413234, 1.34433}, {0.460918, 1.35331}, {0.502923, 1.36225}, {0.136621, 2.13427}, {0.510364, 2.08513}, {0.292188, 2.09307}, {0.0484584, 2.59908}, {0.328597, 2.67853}, {0.418037, 2.39543}, {0.555575, 2.85544}, {0.141857, 2.87505}} Or equally do: Cases[ll, {a_, b_} /; a < .7 && b > 1.] Cases[ll, {_?(# < .7 &), _?(# > 1. &)}] DeleteCases[ll, {a_, b_} /; a >= .7 || b <= 1.] -- Hartmut Wolf