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Re: st: is there a way to determine variable storage type within a dofile


From   Nick Cox <njcoxstata@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: is there a way to determine variable storage type within a dofile
Date   Sat, 10 Dec 2011 09:57:47 +0000

If you are interested in -ds-, check out -findname- (SJ). Go for the
article in SJ 10-2 and the bug-fixed software from the SJ 10-4 files.
As always, installing the software does not depend on a SJ
subscription.

dm0048_1 from http://www.stata-journal.com/software/sj10-4
    SJ10-4 dm0048_1.  Update: Finding variable names / Update: Finding
    variable names / by Nicholas J. Cox, Durham University, UK / Support:
    n.j.cox@durham.ac.uk / After installation, type help findname

dm0048 from http://www.stata-journal.com/software/sj10-2
    SJ10-2 dm0048.  Finding variables / Finding variables / by Nicholas J.
    Cox, Durham University, UK / Support:  n.j.cox@durham.ac.uk / After
    installation, type help findname

-findname- can do what -ds- can and more.

-ds- is and was an official command, but includes several user-written
details. -findname- is user-written, a superset of -ds- with slightly
different syntax.

Nick


On Sat, Dec 10, 2011 at 12:18 AM, Matthew White
<mwhite@poverty-action.org> wrote:

> You can use the -:type- extended macro function. For example:
> sysuse auto, clear
> local type : type foreign
> assigns "byte" to local `type'. For more information on extended macro
> function, see -help extended_fcn- and -help macrolists-.
>
> That said, you might want to try other approaches. -ds, has(type
> string)- will save the names of all string variables in -r(varlist)-.
> Then you can loop over this variable list.
>
> In this case, I might try something like this:
> ***BEGIN***
> label define yesno 0 "no" 1 "yes"
> ds, has(type string)
> foreach var in `r(varlist)' {
>        levelsof `var'
>        if `"`r(levels)'"' == `"`"X"'"' {
>                replace `var' = "1" if `var' == "X"
>                replace `var' = "0" if `var' == ""
>                destring `var', replace
>                label values `var' yesno
>        }
> }
> ds, has(type numeric)
> foreach var in `r(varlist)' {
>        count if `var' == .
>        if r(N) == _N {
>                replace `var' = 0
>                label values `var' yesno
>        }
> }
> ***END***


On Fri, Dec 9, 2011 at 6:52 PM, Sarah Edgington <sedging@ucla.edu> wrote:

>> Is there a way to get Stata to return the storage type for a variable?  I
>> know I can use -describe- to visually see the storage type, but I would like
>> to use the information in an if statement as part of a loop.  Basically, I
>> guess I'm looking for something conceptually like the isreal function in
>> Mata.
>>
>> I am working on importing and cleaning some data that began its life as an
>> Excel spreadsheet.  I have a series of columns in the original sheet that
>> either have an X in them or are blank and I'm trying to turn these into
>> zero-one indicators in my final dataset.  So I'm using -foreach- to loop
>> through the varlist of each of these indicator variables, changing X to 1
>> and missing to zero, then using -destring- to create the final desired byte
>> variable.  The problem is that sometimes a column has no Xs and gets
>> imported as a byte variable (with all observations missing).  So when I get
>> to those variables my loop exits due to type mismatch.  I can work around
>> this with capture but this is not the first time for this project that I've
>> found myself thinking that I want to do a particular thing just with string
>> variables or just numeric variables.  If I were only importing the data once
>> I'd just do it the hard way and make a list of the string variables by hand,
>> but since I'm setting up dofiles to read in new files as we get them, I
>> anticipate that exactly which variables get imported with which storage
>> types will change over time.  In general it seems like I might be able
>> construct cleaner and more manageable code if there were some command that
>> would return the storage type for a variable that I could use to create
>> lists of variables of a given type.  Or is there some other obvious trick
>> I'm missing that would make constructing this type of code easier?

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