st: RE: Using foreach and forval to append data files

["Barclay Matthew (SHEFFIELD TEACHING HOSPITALS NHS FOUNDATION TRUST)" <matthewbarclay@nhs.net>]

Hi Tim,

You can append to an empty dataset, so

clear
forval i = 1/6 {
foreach j of numlist 1 2 8 {
append using `i'_`j'_results
}
}

will do what you want.

Greetings from Trent!

Matt

-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Tim Evans
Sent: 26 March 2013 12:07
To: statalist@hsphsun2.harvard.edu
Subject: st: Using foreach and forval to append data files

Dear all,

Using Stata 11.2, I've created 18 individual results sets that have the following naming schedule:

1_1_results.dta
1_2_results.dta
1_8_results.dta
2_1_results.dta
2_2_results.dta
2_8_results.dta
3_1_results.dta
3_2_results.dta
3_8_results.dta

This continues until the first number reaches 6.

What I am trying to achieve is an automated process of appending all data files and I was using the following code - but this adds a duplication of the file 1_1_results:

use 1_1_results.dta, replace
forval i = 1/6 {
foreach j of numlist 1 2 8 {
append using `i'_`j'_results
}
}

I then tried this:

use 1_1_results.dta, replace
forval i = 2/6 {
foreach j of numlist 1 2 8 {
append using `i'_`j'_results
}
}

Which I then realised that I miss out on any file named:

1_2_***
1_8_***

Other than using the first loop and using -duplicates- to identify and then remove the duplicates, is there a more direct way of using and then appending datasets?

Best wishes

Tim


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