st: Re: egen rowfirst and rowlast quirks

["Michael Blasnik" <michael.blasnik@verizon.net>]

It does sound like a rounding problem due to precision.  How many digits are 
these numbers?  Are you generating doubles or longs?  If you have a number 
that is 24 digits off, I'm wondering how you expect to hold the value 
accurately using double precision?  You should probably type -findit 
precision- and follow some of those links.

Are these actually numeric values or are they identifiers which could be 
held as text?

Michael Blasnik
michael.blasnik@verizon.net

----- Original Message ----- 
From: "Abbe Will" <abbe_will@harvard.edu>
To: "Stata Listserv" <statalist@hsphsun2.harvard.edu>
Sent: Monday, September 11, 2006 3:22 PM
Subject: st: egen rowfirst and rowlast quirks



> Hi,
> In using the -egen newvar=rowfirst(varlist)- and rowlast commands, I am 
> coming up against a strange quirk where occasionally the value of the new 
> variable is not an exact copy of the first or last value as it should be. 
> Out of 900 observations, about 25 first and last values are created which 
> do not match the actual first and last values exactly. Most of these new 
> values are only one digit higher or lower than the original (sounds like 
> rounding, right?), but a few are 2 digits off, one 11 digits off, one 
> 24.... There seems to be no pattern to which numbers get altered and how. 
> My data are positive integers, so there should be no way to round anyway. 
> I'd greatly appreciate any thoughts or comments. Thanks!
>
> -Abbe Will
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