List Manipulation: Conditionally changing y value when x value meets some criteria

*To*: mathgroup at smc.vnet.net*Subject*: [mg108979] List Manipulation: Conditionally changing y value when x value meets some criteria*From*: "Charles Koehler" <cjkphd at wi.rr.com>*Date*: Fri, 9 Apr 2010 03:31:00 -0400 (EDT)

Hello, If possible I could use a little help on this. I have a list of x and y data and based on the value of x I would like to manipulate the value y. I joined the data using: pts=MapThread[{##1}&,{x,y}] I assumed that by testing the x value using #[[1]], I could change the value of y using #[[2]] as shown below. If no manipulation was required based on the value of x, I would keep that point unchanged, but I'm definitely missing something. filtered=If[a<#[[1]]&<b,#[[2]]&=0],{#[[1]],#[[2]]}&,pts] a and b are the range of x values Any insight would be much appreciated. Thanks, Chuck Koehler