Selecting Many Things Rather Than Selecting One Thing From Many

*To*: mathgroup at smc.vnet.net*Subject*: [mg66180] Selecting Many Things Rather Than Selecting One Thing From Many*From*: Gregory Lypny <gregory.lypny at videotron.ca>*Date*: Wed, 3 May 2006 02:44:54 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

Hello everyone, I've discovered another use or need for the Select function, which I suspect requires mapping of some sort. In my previous posts, members of this MathGroup kindly showed me how to apply Select to many columns of a matrix at once. For example, (Select[#1, #1 > K & ] & ) /@ Transpose[theMatrix] will pull out all values greater than K, where K is a number such as 100. But suppose now that K is a list of numbers, such as K={34, 876, 199}, and I simply want to extract or identify all of the rows in the first column of theMatrix equal to any one of those numbers. How would I do that? I started with Select[theMatrix, #[[1]]==any element of list K] and I imagine something similar could be applied to the Position function. Any hint would be much appreciated. Gregory

**Follow-Ups**:**Re: Selecting Many Things Rather Than Selecting One Thing From Many***From:*János <janos.lobb@yale.edu>