Re: st: Extract variable name in order to change it, iteratively

[James Muller <james.muller@internode.on.net>]

If your dates are all the same number of digits you can do some direct 
string processing:


foreach var of varlist `mylist' {
   local len = length("`var'")

   local head = substr("`var'",1,`len'-2)
   local tail = substr("`var'",`len'-1,`len')

   if (`tail' < 70) local date = 2000 + `tail'
   else local date = 1900 + `tail'

   rename `var' `head'`date'
}


and then reshape as you like.

James



David Harrison wrote:


> Along these lines, you could also specify that the two-digit year should be a string variable with, e.g.
>
> reshape long var1_ var2_, i(id) j(year) string
>
> David
>
> -----Original Message-----
> From: owner-statalist@hsphsun2.harvard.edu
> [mailto:owner-statalist@hsphsun2.harvard.edu]On Behalf Of Philip Ryan
> Sent: 02 August 2005 14:06
> To: statalist@hsphsun2.harvard.edu
> Subject: Re: st: Extract variable name in order to change it,
> iteratively
>
>
> You might try an alternative specification of the j index on -reshape-.
>
> Here is a little data set:
>
> . list, clean noobs
>
> id   var1_00  var1_01 var1_88  var1_89  var2_00 var2_01  var2_88  var2_89
>  1        11       13      12        3        4       6       67        8
>  2         9        6      14        5       10       2       18        3
>  3        13        4      11        2       15       8        8        7
>
>
> . reshape long var1_ var2_, i(id) j(year 00 01 88 89)
>
> Data                               wide   ->   long
> -----------------------------------------------------------------------------
> Number of obs.                        3   ->      12
> Number of variables                   9   ->       4
> j variable (4 values)                     ->   year
> xij variables:
>            var1_00 var1_01 ... var1_89   ->   var1_
>            var2_00 var2_01 ... var2_89   ->   var2_
> -----------------------------------------------------------------------------
>
> . li, clean noobs
>
>    id   year   var1_   var2_
>     1      0      11       4
>     1      1      13       6
>     1     88      12      67
>     1     89       3       8
>     2      0       9      10
>     2      1       6       2
>     2     88      14      18
>     2     89       5       3
>     3      0      13      15
>     3      1       4       8
>     3     88      11       8
>     3     89       2       7
>
> That is to say, _you_ may specify the values of the subobservation index rather
> than allow Stata to try and determine them - unsuccesfully on this occasion, as
> you discovered.
>
> Phil
>
>
> Quoting Jeppe Warberg Larsen <jeppewl@gmail.com>:
>
>  
>
> > I have a wide data structure. Each observation consists of a unique
> > identifier (say, id) and some series of annual variables with a
> > two-digit suffix (running in different intervals). Like this:
> >
> > id var1_88 var1_89 ... var1_02 var2_92 var2_93 ... var2_02
> > var3_...................................
> >
> > Now I want to reshape it to long, but stata fails to read the
> > two-digit values after the turn of century (00 01 02), so I need to
> > rename all varibles to a four-digit year.
> >
> > foreach var of varlist var1_88-var100_02{
> > 	//save name of variable in a local string
> > 	//do nessecary string manipulation (I can do that)
> > 	//rename var
> > }
> >
> > My problem seems to be:
> > 1) extracting the name of the current variable
> > 2) rename
> >
> > Do you understand what I'm asking?
> > I'd be glad if someone can help, and please don't tell me that it
> > would be easier to do this manually, because I will need to do this
> > operation many times...
> >
> > Jeppe W. Larsen
> >
> > *
> > *   For searches and help try:
> > *   http://www.stata.com/support/faqs/res/findit.html
> > *   http://www.stata.com/support/statalist/faq
> > *   http://www.ats.ucla.edu/stat/stata/
> >
> >    
>
>  
*
*   For searches and help try:
*   http://www.stata.com/support/faqs/res/findit.html
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/