problems with delayed write: tag list

*To*: mathgroup at smc.vnet.net*Subject*: [mg79877] problems with delayed write: tag list*From*: P_ter <peter_van_summeren at yahoo.co.uk>*Date*: Tue, 7 Aug 2007 01:38:06 -0400 (EDT)

Hello, I have a list of elements of two numbers:myList = {{1,2},{2,7},..}. The first number is in this case always the position. I want to know when the difference is a certain value,myDiff, eg. 5 i=1;myDiff==5; now= Reap[While[i<Length[myList],i++; If[myList[[i,2]]-myList[[i,1]]==myDiff,Sow[i]]];w] My question is: how do I make "nowFunction[myDiff_]:="? I run into tag list errors in the definition when I try that. P_ter