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RE: st: Select a particular test
From
Nick Cox <[email protected]>
To
"'[email protected]'" <[email protected]>
Subject
RE: st: Select a particular test
Date
Fri, 24 Feb 2012 10:31:49 +0000
Typo fix
bysort pat_id: egen OK = max(max(test == "IFA", 0) - max(inlist(test, "DFA", "CULT", "BIN"), 0)))
I still prefer my first solution.
Nick
[email protected]
-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Nick Cox
Sent: 24 February 2012 08:52
To: [email protected]
Subject: Re: st: Select a particular test
At the expense of some clarity
bysort pat_id: egen OK = max(max(test == "IFA", 0) - max(inlist(test,
"DFA", "CULT", "BIN", 0)))
This quite possibly needs too much explanation to be interesting, but
1. The outermost -max()- is an -egen- function and the inner -max(,)-
are calls to the Stata-wide function with that name,
2. If -test- is ever "IFA" then max(test == "IFA", 0) is 1. Similarly
with the other term.
3. So the difference is 1 if and only if the patient has had IFA but
none of the other tests.
Nick
On Fri, Feb 24, 2012 at 12:22 AM, Nick Cox <[email protected]> wrote:
> bysort pat_id : egen select = total(test == "IFA")
> by pat_id : egen reject = total(inlist(test, "DFA", "CULT", "BIN"))
> keep if select & !reject
>
> Your example implies that some tests might be repeated. If there were
> exact rules on such repetition then the code might be shorter; and
> possibly otherwise.
>
> Nick
>
> On Thu, Feb 23, 2012 at 10:57 PM, Peci, Adriana (OAHPP)
> <[email protected]> wrote:
>
>> I have a long form database in which each patient identified by pat_id
>> have up to four tests performed.
>> The test names are:IFA, DFA, CULT, BIN.
>> I want to select/know how many patients had IFA but not DFA, CULT, or
>> BIN.
>>
>> Here is an improvise of my data:
>>
>> Pat_id Test
>> 1 IFA
>> 1 DFA
>> 1 CULT
>> 1 BIN
>> 2 BIN
>> 2 IFA
>> 2 DFA
>> 3 IFA
>> 4 DFA
>> 4 CULT
>> 4 CULT
>>
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