Using integ function in a loop

[Haaris Mateen]

Hi,

I have a set of datafiles - file_1 to file_10. Each file looks like the following:

Y	X
9	1
15	2
6	3
23	4

I wanted to run a loop that gets by each file, using the integ function to numerically integrate y on x and generate a new column with the value of the integrals, called a.

I wrote a loop like this:

forvalues i = 1/10{
use file_`i', clear
integ y x, generate(a)
save file_`i', replace
}

Curiously enough, I can't run this even if I can run the inner commands by themselves. The error I get is "no observations", r(2000). Can you please tell me where I am going wrong?

Thanks!
Haaris

[Jorrit Gosens]

The code below, which is exactly what I understand you are trying, runs fine.

Troubleshooting this will require an example of your actual data with dataex, see the FAQ on how and why: https://www.statalist.org/forums/help#stata
One issue could be one of your variables is string. Other issues might also be spotted if we see an example of your data as is.

* Example generated by -dataex-. To install: ssc install dataex
clear
input byte(y x)
 9 1
15 2
 6 3
23 4
end


save file_1, replace
save file_2, replace
save file_3, replace


forvalues i = 1/3{
use file_`i', clear
integ y x, generate(a)
save file_`i', replace
}