Re: Help! Delete Casses based on column
- To: mathgroup at smc.vnet.net
- Subject: [mg58345] Re: Help! Delete Casses based on column
- From: Rolf Mertig <rolf at mertig.com>
- Date: Tue, 28 Jun 2005 21:56:43 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
>I need to take a large numeric matrix and remove all the rows that have a >value less than X in column N Mathematica 5.1 for Linux x86 (64 bit) Copyright 1988-2004 Wolfram Research, Inc. -- Motif graphics initialized -- In[1]:= !!f.m f[m_?MatrixQ, n_Integer, threshold_?NumberQ] := Select[m, #1[[n]] > threshold & ]; test = Table[Random[],{5000},{5000}]; Print[Timing[r=f[test, 1234, .2];]] ; Print[Length[r]]; In[1]:= <<f.m {0.32995 Second, Null} 3981 --- Greetings, Rolf Mertig