Re: st: rename

[Nick Cox <njcoxstata@gmail.com>]

I'd agree with the principle but not the way to do it. -assert- is
intended to check whether something is true of the data. In principle
it checks every observation to see if something is true of every
observation. I don't know _exactly_  how smart it is at spotting tests
that are independent of the data -- I'd expect some considerable
intelligence on that front -- but if only on stylistic grounds I'd
recommend something more direct like

if `oldcount' != `newcount' {
     di as err "old # is `oldcount'; new # is `newcount': election fraud?"
}

I'd assert that you don't see examples like David's in Stata's own code.

Nick

On Thu, Aug 9, 2012 at 5:44 PM, David Radwin <dradwin@mprinc.com> wrote:
> Also, if you want to automate the process for checking whether the number
> of variables in the old list and the new list are the same, you could give
> the two mycount macros different names and use the -assert- command like
> this:
>
> . assert `oldcount' == `newcount'
>
> See Gould, W. 2003. Stata tip 3: How to be assertive. Stata Journal 3:
> 448. http://www.stata-journal.com/article.html?article=dm0003
>
> David
>
> --
> David Radwin
> Senior Research Associate
> MPR Associates, Inc.
> 2150 Shattuck Ave., Suite 800
> Berkeley, CA 94704
> Phone: 510-849-4942
> Fax: 510-849-0794
>
> www.mprinc.com
>
>
>> -----Original Message-----
>> From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-
>> statalist@hsphsun2.harvard.edu] On Behalf Of Nick Cox
>> Sent: Thursday, August 09, 2012 8:32 AM
>> To: statalist@hsphsun2.harvard.edu
>> Subject: Re: st: rename
>>
>> Good news. You may be interested for future coding in small
>> abbreviations of your code.
>>
>> gen rutgers2 = "m" + string(marker) if used == 0
>> replace rutgers2 = rutgers if used == 1
>> local end = _N
>> forvalues i = 1/`end' {
>>         local next = rutgers2[`i']
>>         local mynewvars `mynewvars' `next'
>> }
>>
>> becomes
>>
>> /// assumes only values are 0 or 1
>> gen rutgers2 = cond(used == 0, "m" + string(marker), rutgers)
>>
>> forvalues i = 1/`=_N' {
>>         local mynewvars `mynewvars' `=rutgers[`i']'
>> }
>>
>> On Thu, Aug 9, 2012 at 4:26 PM, Airey, David C
>> <david.airey@vanderbilt.edu> wrote:
>> > .
>> >
>> > Thanks to Nick and David, I got my rename groups code to work. Using
>> > macro expansion I create a local macro containing the new variable
>> > names that are in a string variable in a data set that is correctly
>> > ordered by row to match a wide dataset in terms of variable order. I
>> > create another local of the variables names in the wide dataset to be
>> > renamed using the unab command. Then the new rename groups command
>> > works great here, for 2129 variables, where the oldvars and newvars
>> > are represented by locals.
>> >
>> > use markers_used.dta, clear
>> >
>> > // make local containing new variable names
>> > // from a string variable contents (same order
>> > // as variables in dataset to be renamed)
>> > gen rutgers2 = "m" + string(marker) if used == 0
>> > replace rutgers2 = rutgers if used == 1
>> > local end = _N
>> > forvalues i = 1/`end' {
>> >         local next = rutgers2[`i']
>> >         local mynewvars `mynewvars' `next'
>> > }
>> > local mycount : word count `mynewvars'
>> > display "`mycount'" // check if same as below
>> >
>> > // get local containing old variable names
>> > use chr2_geno.dta, clear
>> > unab myoldvars : m*
>> > local mycount : word count `myoldvars'
>> > display "`mycount'" // check if same as above
>> >
>> > // rename using new rename groups command
>> > rename (`myoldvars') (`mynewvars')
>> > drop m*
>> > describe, short
>> >
>> >
>> > // same effect in loop
>> > /*
>> > use chr2_geno.dta, clear
>> > drop id famid
>> > local nvars = r(k)
>> > use chr2_geno.dta, clear
>> > forvalues i = 1/`nvars' {
>> >         local oldname : word `i' of `myoldvars'
>> >         local newname : word `i' of `mynewvars'
>> >         rename `oldname' `newname'
>> > }
>> > drop m*
>> > describe, short
>> > */
>> >
>> >
>> >
>> >
>> >> sysuse auto
>> >> rename (*) (<new list>)
>> >>
>> >> will work.
>> >>
>> >> Nick
>> >
>> >>> Maybe you could run it through a loop where the first word of the
>> first
>> >>> macro gets changed to the first word of the second macro, etc.? Like
>> >> this:
>> >>>
>> >>> * Make fake dataset
>> >>> set more off
>> >>> clear
>> >>> set obs 1
>> >>> forvalues i = 1/1000 {
>> >>>      gen oldvar`i' = .
>> >>>      }
>> >>>
>> >>> * Make list of new variable names
>> >>> forvalues i = 1/1000 {
>> >>>      local newnames `newnames' newvar`i'
>> >>>      }
>> >>>
>> >>> * Change all variable names
>> >>> local j = 1
>> >>> unab original : oldvar*
>> >>> forvalues j = 1/1000 {
>> >>>      local oldname : word `j' of `original'
>> >>>      local newname : word `j' of `newnames'
>> >>>      rename `oldname' `newname'
>> >>>      }
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