There is one more problem with Lou's code, apart from the points made by
Nick Cox & Nick Winter :
-replace syphilis = 1- is a valid command; but -replace syphilis == 1-
is not.
-syphilis == 1- is a statement, that is either true or false, and can be
evaluated for every value of syphilis.
As Nick Winter points out, the last section will always resolve to 1;
meaning TRUE.
How Lou shold change it depends on what he actually means.
If Lou intends -syphilis- to exclude those subjects with -lbresc- either
"POSITIVE 1:128" or "POSITIVE 1:16", he needs
replace syphilis=1 if visit==1 & lbcd=="SYP_RPR" & (lbresc!="POSITIVE
1:128" & lbresc!="POSITIVE 1:16")
If Lou intends to include subjects with these two values of -lbresc-, he
needs
replace syphilis=1 if visit==1 & lbcd=="SYP_RPR" &
(lbresc=="POSITIVE 1:128" | lbresc =="POSITIVE 1:16")
BW
Paul Seed
Date: Thu, 9 Oct 2008 08:55:17 -0700 (PDT)
From: lou apicella <[email protected]>
Subject: st: if programming command
Hello Statalisters,
I'm trying to convert some logical statements into nested if statements.
I feel the two statements below should give the same result but they do
not. What am I do wrong here?
Thanks in advance.
Lou.
replace syphilis=1 if visit==1 & lbcd=="SYP_RPR" & (lbresc!="POSITIVE
1:128" | lbresc!="POSITIVE 1:16")
if visit==1 {
if lbcd=="SYP_RPR" & (lbresc!="POSITIVE 1:128" | lbresc!="POSITIVE
1:16" ) {
replace syphilis==1
}
}
Paul T Seed MSc CStat, Lecturer in Medical Statistics,
tel (+44) (0) 20 7188 3642, fax (+44) (0) 20 7620 1227
Wednesdays: (+4) (0) 20 7848 4148
[email protected], [email protected]
King's College London, Division of Reproduction and Endocrinology
St Thomas' Hospital, Westminster Bridge Road, London SE1 7EH
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