Merging many data file

[Standard Adejuwon]

Is there a way I can merge more than 10 data file into one?

I'm trying to use:

foreach file in d.dat d1.dat....... {
sort id
merge 1:1 id using d5.dat

}

It's telling me " no variables defined"

Please, any suggestions?

[Sven-Kristjan Bormann]

You need to have at least one dataset already in memory, otherwise, you cannot merge them. Furthermore, your code is incorrect.

foreach file in d.dat d1.dat....... {
merge 1:1 id using `file', nogen
}

You did not reference the local macro needed to loop over the files. I also added an option to prevent the creation of the _merge variable, which you would need to drop anyways after each merge.

[Standard Adejuwon]

Thanks Bormann

[Standard Adejuwon]

Use Users\user\Desktop\datafolder\d.dta

While I referenced the local macro using:

cd "C: \Users\user\Desktop\datafolder"
local datasets: dir "Users\user\Desktop\datafolder" files "*.dta"

Tempfile resource

foreach dataset in local datasets {
sort id save resource, replace
merge 1:1 id using C:\Users\user\Desktop\datafolder\d1.dta.
}
It only merged d.dta and d1.dta. But I want stata to merge all other files in datafolder.

Thanks.

[Andrew Musau]

Just start with a simple loop.

use d, clear
foreach file in d1 d2...dN{
    merge 1:1 id using `file', nogenerate
}

Assumes that each dataset has the variable "id" present.

[Standard Adejuwon]

Thanks Andrew.

I've not still got my desired result.

What this loop did was that it merged the 'use' dataset and the 'master' dataset only.

I actually want stata to merge all the datasets in the datafolder.

E.g. The data folder contains d1, d2, d3........dN

[Andrew Musau]

What this loop did was that it merged the 'use' dataset and the 'master' dataset only.

Does the loop terminate with an error? If not, the merges were successful. I cannot advise further absent a data example. You can randomly pick 3 datasets and provide the first 10 observations of each so I illustrate the procedure. Just copy and paste the result of the following for each of the datasets. Replace the names of the datasets accordingly.

use d, clear
dataex in 1/10

use d3, clear
dataex in 1/10

use d7, clear
dataex in 1/10