Stata tempfile not found when using append, save, use

Question

I have a short do-file in Stata that uses a loop to read in some datasets, one at a time, and append them to a tempfile. However, this tempfile is not found when trying to open it at the end.

Running this script on Windows and MacOS (Stata 17):

clear
set more off
set trace on

local patha "<patha>"
local pathb "<pathb>"

use "`pathb'fileb.dta", clear

levelsof pathb_variable, local(l)

tempfile append_file

foreach i of local l {
    capture confirm file "`patha'filea_`i'.dta"
    if _rc==0 {  
        capture append using `append_file'
        save `append_file', replace
    }
    
}
use `append_file', clear

As set trace is on, I can see that the first line that runs in Stata, before clear and set more off is:

do "C:\Users\...\AppData\Local\Temp\10\STD7578_000000.tmp" on Windows, and

do "/var/folders/02/50xtwnrn5yb_wrh_md7s23br0000gn/T//SD26113.000000" on Mac.

The error message that appears, just after use `append_file', clear is run, is:

file C:\Users\...\AppData\Local\Temp\10\ST_7578_000001.tmp not found on Windows, and

file /var/folders/02/50xtwnrn5yb_wrh_md7s23br0000gn/T//S_26113.000001 not found on Mac.

In both cases, it looks like a different tempfile being created than is being accessed? The tempfile filename it is trying to open has replaced 'D' with '_' and the last digit is '1' not '0'.

How to make this script work?

Answer 1

I think it is less error prone to save the tempfile as an empty file to append to instead of using capture without handling the error code.

use "`pathb'fileb.dta", clear

levelsof pathb_variable, local(l)

tempfile append_file

preserve 
  clear
  save `append_file', emptyok
restore

foreach i of local l {
    capture confirm file "`patha'filea_`i'.dta"
    if _rc==0 {  
        append using `append_file'
        save `append_file', replace
    }
    
}
use `append_file', clear