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RE: st: another data cleaning question


From   "Nick Cox" <n.j.cox@durham.ac.uk>
To   <statalist@hsphsun2.harvard.edu>
Subject   RE: st: another data cleaning question
Date   Mon, 24 Jun 2002 10:02:27 +0100

Babigumira Ronnie replied to Roger Newson's suggestion:

> > Use the -int- function (see -help functions-). In this case, you might
> > type
> >
> > gene cropcod2=int(varcode/100)
> > list if cropcod2!=cropcode
> > assert cropcod2==cropcode
> > drop cropcod2
> >
> > and Stata will generate a new variable -cropcod2-, which should be equal
> > to -cropcode- if the data are consistent. Stata will then list
> consistent
> > cases, and halt execution if there are any inconsistent cases, and drop
> > the variable -cropcod2- otherwise.
> >
> > I hope this helps.
> >

> Many thanks. It works however, I have a slight complication, some of the
> variety codes are more than 5. Here is an example (also included is the
> new variable cropcod2)
>
>         villcode  cropcode   cropcod2       varcode
> 1.      1531002       110        110         11001
> 2.      1531002       110        110         11001
> 377.    1360100       110       1101        110104
> 378.    1362000       110       1101        110104
>
> The first 2 varcodes have 5 digits and hence
>
> . gen cropcod2=int(varcode/100)
>
> would work just fine, however, the last two have varcodes with 6 digits
> which would therefore mean that I would need to rewrite the syntax to
>
> . gen cropcod2=int(varcode/1000)
>
> This would however truncate that 5 digit varcodes and the resulting
> cropcod2 would have 2 digits.
>
> I would therefore like to put in a condition that would allow the first
> truncation to be done only if the number of digits in varcode is 5 and
> then replace cropcod2 with a new truncated figure if the varcode has 6
> digits. I have searched the manual and I still haven't found it. Might you
> (or anyone else reading) have any idea how I can do this.


I suggest that any test be in terms of the first three
characters of the string equivalent.

list if string(cropcode) != substr(string(varcode,1,3))

More generally, whenever codes are pseudo-numeric, there
are several advantages to holding them as strings.

Nick
n.j.cox@durham.ac.uk

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