Too many variables specified error with keep and browse command

[Jane Evans]

I have created a large local (called stubs) of variable stubs with wild cards e.g. "var1_* var2_* var3_*". The list is quite long (~1,000 variables) when expanded out. When I execute either keep stubs or browse stubs, I'm getting an error message "too many variables specified", which I've never seen before. As the dataset is currently loaded into Stata, I'm not sure why keeping or browsing a smaller subset would cause an issue. Any ideas?

[Marcos Almeida]

Maybe it is related to the - maxvar - specification plus the Stata flavor.

According to the Stata Manual,

The maximum number of variables in your dataset is limited to
maxvar. The default value of maxvar is 5,000 for Stata/MP and
Stata/SE, and 2,048 for Stata/IC. With Stata/MP and Stata/SE, this
default value may be increased by using set maxvar. The default
value is fixed for Stata/IC.

[William Lisowski]

I don't think the problem is a result of maxvar, because as you say, the dataset is loaded in memory, so any exhaustive list of variables shouldn't contain more variables than there are in the dataset.

What happens if you try

keep *

And, are you sure you haven't accidentally duplicated some of the stubs? Your sample list of stubs appears to be invented; perhaps your actual list is more complicated and you've accidentally duplicated things. The following example demonstrates that the expanded list does not have duplicates removed before the variables are counted.

. set maxvar 2048

. forvalues i=1/2048 {
  2. generate v`i'=.
  3. }

. keep *

. keep * *
too many variables specified
r(103);

.