Alvine wrote:
I have a date set with 1 line per patient, and many measures by patient
(mes1, mes2, mes3, ...). The number of measurement is given by the nb_mes
variable.
id mes1 mes2 mes3 mes4 nb_mes
1 30 21 25 46 4
2 26 24 2
3 14 15 13 3
For each patient, I would like to calculate the difference :
mes2-mes1, mes3-mes, ..., until : mes`nb_mes'-mes1
I've tried this:
forvalues i=2/`nb_dos' {
local im1=`i'-1
gen diff`im1'=mes`i'-mes1
}
------------------------------------------------------
What is nb_dos? Do you mean nb_mes?
Even `nb_mes' does not work; nb_mes is a variable, and you can
not treat it as a local macro which is a kind of constant.
You must know something about the maximum number of measurements
(below I assume 4), so just:
clear
input id mes1 mes2 mes3 mes4
1 30 21 25 46
2 26 24 . .
3 14 15 13 .
end
forvalues i=2/4 {
gen diff`i'=mes`i'-mes1
}
list, clean
id mes1 mes2 mes3 mes4 diff2 diff3 diff4
1. 1 30 21 25 46 -9 -5 16
2. 2 26 24 . . -2 . .
3. 3 14 15 13 . 1 -1 .
(I suggest that you name the difference mes7-mes1 diff7, not diff6)
Hope this helps
Svend
________________________________________________________
Svend Juul
Institut for Folkesundhed, Afdeling for Epidemiologi
(Institute of Public Health, Department of Epidemiology)
Vennelyst Boulevard 6
DK-8000 Aarhus C, Denmark
Phone, work: +45 8942 6090
Phone, home: +45 8693 7796
Fax: +45 8613 1580
E-mail: [email protected]
_________________________________________________________
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