Creating rates using foreach

[Jamie Lopez]

I have a range of variables for counts of diagnoses each beginning "cat_" and another variable "population"

I would like to create a new variable of the incidence e.g. "inc_cat_cardio"

I can do this using:

gen inc_cat_cardio = cat_cardio / population

However if I do:

foreach cat of var cat* {
gen inc_`var' =  `var' / population
}

I get the following error: "/population invalid name"

Help suggests that this is a typo but I have checked this and am using exactly the same spelling with and without foreach

Can anybody advise on what I am doing wrong?

Thanks

[Nick Cox]

Your loop is the wrong way round. Your declared macro within the loop is cat not var, so Stata can only replace a reference to var with an empty string, hence the problem report which is that / population makes no sense as a name which is one of several possibilities after the equals sign.

You need

foreach cat of var cat* {    
    gen inc_`cat' =  `cat' / population
}

or if you prefer

foreach var of var cat* {      
    gen inc_`var' = `var' / population  
}

[Jamie Lopez]

Ah thanks. Sorry for the stupid question!