Hi dear statalister,
I have a question on loop within loop. I have the following data set
year month date a b c
88 1 1 .2 .5 .3
. 1 2 .3 .6 .4
. 1 3 .4 .7 .5
. 2 1 .1 .2 .7
. 2 2 .4 .5 .9
. 2 3 .6 .7 1
89 1 1 .2 .5 .3
. 1 2 .3 .6 .4
. 1 3 .4 .7 .5
. 2 1 .1 .2 .7
. 2 2 .4 .5 .9
. 2 3 .6 .7 1
I could program the correlation by year as follows,
g corrab = .
forvalues i = 1988(1)2003{
matrix accum R`i' = a b c if year == `i', nocons dev
matrix R`i' = corr(R`i')
replace corrab = R`i'[2,1] if year == `i' & corrab == .
}
However, now I want to calculate the correlation between a and b by year
and month. What should I do?? I tried the following, but it doesnot work.
forvalues i = 1988(1)2003 {
local j = 1
while `j' < 13{
matrix accum R`i'`j' = a b c d e if year == `i' & month == `j',
nocons dev
matrix R`i'`j' = corr(R`i'`j')
replace corrab = R`i'`j'[1,1] if year == `i' & month == `j' &
corrab == .
local `j' = `j' + 1
}
}
Thanks a lot for your kind help.
Best,
Le
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