.N is a special missing, to distinguish NIU, from don't know, refused,
invalid, etc. The complete set of letters, plus '.' and '._' are available
in SAS. Stata has a similar set, but the most important thing to remember
is that in SAS missings are the SMALLEST value and in Stata they are the
LARGEST value. Also, SAS is not case sensitive (in general) while Stata is.
Bryan Sayer
Statistician, SSS Inc.
-----Original Message-----
From: Nick Cox
To: [email protected]
Sent: 7/8/03 3:18 PM
Subject: st: RE: STATA equivalent to SAS subsetting "else if" statements?
Deborah Garvey
> I have generally used SAS for data manipulation, so I am
> not familiar with the best way to code the equivalent of
> the subsetting "else if" statement in STATA.
>
> This SAS code defines RACEETH hierarchically, based on the
> value of HISPANG and RACEG. It only permits RACEETH to
> change once (from default missing to a valid value), at the
> first occurrence of a true IF statement:
>
> if hispang = 0 then do;
> if raceg = 1 then raceeth = 1;
> else if raceg = 2 then raceeth = 2;
> else raceeth = 3;
> end;
> else if hispang = 9 then raceeth = .N;
> else if hispang ge 1 and hispang < 9 then raceeth = 7;
>
> How do I accomplish this in STATA?
In Stata
(cf. http://www.stata.com/support/faqs/res/statalist.html#spell)
you have to flip everything round to go on the
right-hand side. Also == tests for equality; = assigns RHS
to LHS only.
This looks like
gen raceeth = .
replace raceeth = 1 if hispang == 0 & raceg == 1
replace raceeth = 2 if hispang == 0 & raceg == 2
replace raceeth = 3 if hispang == 0 & raceeth == .
replace raceeth = <whatever> if hispang == 9
replace raceeth = 7 if hispang >= 1 & hispang < 9
Or we could start with
gen raceeth = 1 if hispang == 0 & raceg == 1
replace raceeth = 2 if hispang == 0 & raceg == 2
replace raceeth = 3 if hispang == 0 & raceeth == .
replace raceeth = <whatever> if hispang == 9
replace raceeth = 7 if hispang >= 1 & hispang < 9
Somebody else please say what .N is in SAS as I have
.Not a clue.
Nick
[email protected]
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