st: mata for-if-else

["Abhimanyu Arora" <abhimanyu.arora@student.kuleuven.be>]

Dear statalist, 
I have simplified my problem to a large extent, but essentially has to do
with using for-if-else commands in mata. I would like to create a matrix 'a'
whose values depend on an existing matrix 'b' (both are 1000X1 vectors to be
precise). I need to tell mata the dimension of a first. But all I get after
executing the commands below is the original vector 'a'. What could be the
possible error? I have tried adding and removing braces but it is not
working... 




a=J(1000,1,.)
for(i=1,i<1001,i++) {
if (b[i]==1){
a[i]=2
}
else {a[i]=3
}
}
a
end


Thanks a lot
Abhimanyu

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