<>
" I can't see any advantage is using -ds- first in this example."
Neither do I, and that is why I used the approach you are suggesting in
later posts, as witnessed here:
http://www.stata.com/statalist/archive/2009-10/msg00459.html
It is pretty much akin to what Maarten and I discussed yesterday in
http://www.stata.com/statalist/archive/2009-10/msg00475.html and follow-ups:
-postfile- is a very general tool, but in the case described by John,
-statsby-, as suggested by Maarten, sufficed.
The same principle applies to Michael`s query: -ds- takes care of this _and
more_, but -foreach- is happy to expand a standard -varlist- for Michael...
HTH
Martin
-----Ursprüngliche Nachricht-----
Von: [email protected]
[mailto:[email protected]] Im Auftrag von Nick Cox
Gesendet: Sonntag, 11. Oktober 2009 19:53
An: [email protected]
Betreff: RE: st: RE: AW: finding date occurrences within a specified range,
searching in multiple variables
Let me focus on one detail implicit in the sequence of postings by
Martin Weiss on this subject.
As -foreach- can take a varlist, you can go directly to
foreach var of varlist t_* {
I can't see any advantage is using -ds- first in this example. The only
obvious reason for using -ds- would be as a filter to include (e.g.)
numeric variables only.
Nick
[email protected]
Michael McCulloch
Thanks Nick, what I meant more broadly was whether multiple date
variables, all whose names begin with "t_", for example t_date1,
t_date2, etc., could be specified in this line, in which the second
date is changed for a wider time frame:
> foreach var of varlist `r(varlist)'{
> gen byte seek`var' = `var' > td(1nov2009) & t_date <
td(9nov2009)
I also attempted a modification, which rather than giving me the id of
only records in which any date (t_*) was within 1nov to 9nov, instead
gave me all records and all dates:
qui ds t_*
sort id
foreach var of varlist `r(varlist)'{
gen byte seek`var' = `var' > td(1nov2009) & `var' < td(9nov2009)
list id seek* if `var'!=0
}
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