help with foreach var of local varlist

[Sandra AJ Alba]

Hi all,

I am trying to do some code over a selection of variables in a dataset. So i wanted to create a local variable with all variables, and then loop over all varialbes by calling up that local. But it doesn't work. any suggestions?

Thanks, Sandra

des _begin-_end, varlist
return list varlist

foreach var of local varlist{
di `var'
}

[daniel klein]

On expressions like "it does't work" please see FAQ 12.

You never define local macro varlist, this is why there are zero elements to loop over.

Probably you want

foreach var of varlist _begin-_end {

}

Best
Daniel

[Klaudia Erhardt]

Hi Sandra,

you can also do it the way you described, but you have to copy the return value of describe, varlist into a local (named 'vars' in syntax below), and then use that local in the foreach-loop

quietly describe _begin - _end, varlist
local vars = r(varlist)
foreach x of varlist `vars' {
    display " `x' "
}

Greetings, Klaudia

[Klaudia Erhardt]

Hi Sandra,

you can also do it the way you headed for, but you have to copy the return value of describe, varlist into a local (named 'vars' in syntax below), and then use that local in the foreach-loop

quietly describe _begin - _end, varlist
local vars = r(varlist)
foreach x of varlist `vars' {
    display " `x' "
}

Greetings, Klaudia

[daniel klein]

While there is nothing wrong with the basic approach, the line

local vars = r(varlist)

can be dangerous, especially in older Stata versions (see Cox, 2008). Coding

local vars `r(varlist)'

is safer. Also see ds, and unab for such approaches.

Best
Daniel


Cox, N.J. (2008). Stata tip 70: Beware the evaluating equal sign. The Stata Journal, 8(4): pp. 586–587.

[Sandra AJ Alba]

many thanks!