Re: st: Expanding characteristics of variables with 32-character names

[Sergiy Radyakin <serjradyakin@gmail.com>]

Matt,
I can reproduce the problem both in Stata 9 and Stata 12 with the
following code:

clear
forval i=1/32 {
  local vn=substr("abcdefghijklmnopqrstuvwxyz0123456789",1,`i')
  assert strlen(`"`vn'"')==`i'
  generate `vn'=999
  char `vn'[`vn'] 1
  display `"`i' `vn'"'
  di `"`:char `vn'[`vn']'"'
  assert `:char `vn'[`vn']'==1
  di `"{``vn'[`vn']'}"'
  assert ``vn'[`vn']'==1
}
describe

I can add that the Mata's st_global() produces correct result, so
that's another alternative. And I can add that I never used the
simplified access to characteristics as you used varname[varchar] in
Stata, always using a char macro expansion or recently more often the
Mata approach.

In my opinion it looks like a bug. I recall older specifications of
the dta file format had a typo around the characteristics storage
description. This was corrected around v11, but the typo came back in
the Stata 13th help for data file description (I have notified
StataCorp techsupport on  2013.06.13). Not sure if this is related.

Best, Sergiy Radyakin

On Mon, Aug 5, 2013 at 5:14 PM, Matthew White <mwhite@poverty-action.org> wrote:
> Hi Statalist users,
>
> Using Stata 13 on Windows 7, I'm attaching a characteristic to
> variables and then using single quotes to expand the characteristic.
> For example:
>
> sysuse auto, clear
> char foreign[Y] 1
> char list foreign[]
> display `foreign[Y]'
>
> However, I'm having trouble when the variable name is 32 characters long:
>
> sysuse auto, clear
>
> char foreign[Y] 1
> char list foreign[]
> display `foreign[Y]'
>
> local var : di _dup(32) "x"
> rename foreign `var'
>
> char list `var'[]
> display ``var'[Y]'
>
> `var'[Y] still exists, but ``var'[Y]' doesn't expand to anything. Has
> anyone seen this problem before?
>
> I can get around it by using the -:char- extended macro function:
>
> display `:char `var'[Y]'
>
> This correctly displays 1. However, I'd prefer to use the ``var'[Y]'
> syntax if possible.
>
> Thank you,
> Matt
>
> --
> Matthew White
> Senior Project Associate
> Innovations for Poverty Action
> 101 Whitney Avenue, New Haven, CT 06510 USA
> www.poverty-action.org
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