There is no reason to expect -if- to accept
value labels in this way. Unless explicitly
instructed, -if- deals with values, not
value labels. Thus
if ncyear == 2000/1
is being interpreted as
if ncyear == 2000
as the expression 2000/1 evaluates
to 2000. On the other hand you evidently
have no years that are 2001/2, i.e. 1000.5.
The syntax is
if <exp>
where <exp> denotes an expression, which will
be evaluated before being used.
On the other hand, something like this
should work:
tab ncyear if ncyear == "2000/1":name
Nick
n.j.cox@durham.ac.uk
Paul O'Brien
> I am not sure what the problem is here, but 'if' is not working for
> some date labels.
> year_f is OK up to 2000/1 but beyond that give no observations.
>
> .egen year_f = ncyear(date_v), m(4)
>
> . table year_f
> ----------------------
> year_f | Freq.
> ----------+-----------
> 1997/98 | 44,023
> 1998/99 | 42,654
> 1999/0 | 42,944
> 2000/1 | 42,127
> 2001/2 | 41,520
> 2002/3 | 41,463
> 2003/4 | 40,057
> ----------------------
>
> . table ageint if year_f==2000/1
>
> ----------------------
> ageint | Freq.
> ----------+-----------
> 12 | 5
> 13 | 36
> 14 | 131
> 15 | 346
> etc
>
> . table ageint if year_f==2001/2
>
> no observations
>
> r(2000);
>
> But there are observations for year_f==2001/2
>
> . table ageint year_f
>
> --------------------------------------------------------------
> ----------
> -
> | year_f
> ageint | 1997/98 1998/99 1999/0 2000/1 2001/2 2002/3
> 2003/4
> ----------
> +--------------------------------------------------------------
> 10 | 1 1 2
> 1
> 1
> 11 | 2 2 2 1
> 2
> 1
> 12 | 2 3 2 5 4
> 3
> 7
> 13 | 13 20 17 36 22
> 20
> 12
> 14 | 73 49 64 131 110
> 101
> 99
> 15 | 238 259 238 346 362
> 302
> 325
>
> If I try -list- I get the same thing:
>
> . list if year_f==2000/1
>
> Observation 129622
>
> clin_s~e RC clin_w~k connum
> 2
> date 15-Feb-01 dob 04-Apr-63
>
> etc
>
>
> Observation 129623
>
> clin_s~e RC clin_w~k D-
> CON connum 1 date 07-Feb-01 dob 06-Apr
> -77
>
> etc
>
> . list if year_f==2001/2
>
> This last command gives nothing.
*
* 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/
