Nested Loop Containing Count of Different Number of Variables Within each wave

[Sue Sheffield]

Hi STATA-Peeps,

I've got 10 waves of data from a panel. Each contains a series of health condition variables [hcondn1....hcondn5...], but they all contain a different number of variables in this series (ranging from hcondn5 to hcondn13).

I can nest loops within loops, but can someone please help me with the code for only running my foreach loop the right amount of times depending on the wave number please?

Here is my foreach loop code so far:


foreach w in b c d e f g h i j k {

// find the wave number using "String Position" count (strpos)

local wave_nr=strpos(" bcdefghijk","`w'") // Counts to string posn _234567891011

local varcount = 0
foreach hc of varlist `w'_hcondn*{
varcount =+1
}

/* The line below stops the code at the first wave that doesn't have 8 "hcondn" variables in it */

use id `w'_hcondno1 `w'_hcondno2 `w'_hcondno3 `w'_hcondno4 `w'_hcondno5 `w'_hcondno6 ///
`w'_hcondno7 `w'_hcondno8 using "$Originals/`w'_indresp", clear

rename `w'_* *

gen wave=`wave_nr'

save temp`w', replace


Thanks for your help. I have tried a bit, but not quite integrated the two loops quite right.

Cheers!

SCE

[William Lisowski]

You can use wildcards in the varlist on the use command. Try

use id `w'_hcondno* using "$Originals/`w'_indresp", clear

I am unsure of what you are trying to do with your varcount loop. I don't think it is needed, or else it should appear after the dataset has been read in.

[Nick Cox]

I agree with William Lisowski.

The varcount code won't work any way, unless you move some of the code to Mata.

local ++varcount

would work but you don't need a loop.

This appears to be the start of what you want, but sorry, I can't follow the rest of it.

forval wave_nr = 2/11 { 

    local w = word("`c(alpha)'", `wave_nr') 

    * must read n the data before this 
    unab varlist : `w'_hcondn* 
    local varcount :  word count `varlist'

[Sue Sheffield]

You can use wildcards in the varlist on the use command. Try

use id `w'_hcondno* using "$Originals/`w'_indresp", clear

I am unsure of what you are trying to do with your varcount loop. I don't think it is needed, or else it should appear after the dataset has been read in.

Thanks. I discovered there were also *hcond variables in there but only ion one wave, so had to add those in there as well. But otherwise just simply using `w'_hcond* worked for all the others with different endings.