Store list

[Rui Tiago]

Dear Stata users,
I would like to create a variable that is the list of the countries that I am using. "label list country" or "tab country" does not permit to store my results (or the list of the countries). Could anyone please tell me a way to do this?
Thank you

[Nick Cox]

The variable already exists -- it's called country. But does

levelsof country

do what you want?

[Rui Tiago]

Thank you, Nick Cox for your answer.
The problem is that I have cross-sectional data and each country appears more than once, and I don't want to delete any observation.
Your suggestion creates a variable that lists the countries in one line, but I would like to have each country in one line, so for example, if I have 20 countries I want to create a variable that is a matrix 1x20.

[Nick Cox]

We can't have an easy discussion if variable means anything you want it to mean, and not even consistently. On Statalist there is one clear definition of variable, Stata's definition that a variable is (in other terms) a column in the dataset that has a variable name and a set of values,

No variable is created by levelsof, at most a local macro (not a variable) and a stored result (not a variable), but you say that it's not what you want.

You can't have any variable that has a different number of observations from that in the entire dataset.

You can have a matrix in Stata so long as the values of your variable is numeric.

You can have a matrix in Mata if the values are string.

. sysuse census, clear
(1980 Census data by state)

.  mata : uniqrows(st_sdata(., "state"))
                    1
     +-----------------+
   1 |        Alabama  |
   2 |         Alaska  |
   3 |        Arizona  |
   4 |       Arkansas  |
   5 |     California  |
   6 |       Colorado  |
   7 |    Connecticut  |
   8 |       Delaware  |
   9 |        Florida  |
  10 |        Georgia  |
  11 |         Hawaii  |
  12 |          Idaho  |
  13 |       Illinois  |
  14 |        Indiana  |
  15 |           Iowa  |
  16 |         Kansas  |
  17 |       Kentucky  |
  18 |      Louisiana  |
  19 |          Maine  |
  20 |       Maryland  |
  21 |  Massachusetts  |
  22 |       Michigan  |
  23 |      Minnesota  |
  24 |    Mississippi  |
  25 |       Missouri  |
  26 |        Montana  |
  27 |    N. Carolina  |
  28 |      N. Dakota  |
  29 |       Nebraska  |
  30 |         Nevada  |
  31 |  New Hampshire  |
  32 |     New Jersey  |
  33 |     New Mexico  |
  34 |       New York  |
  35 |           Ohio  |
  36 |       Oklahoma  |
  37 |         Oregon  |
  38 |   Pennsylvania  |
  39 |   Rhode Island  |
  40 |    S. Carolina  |
  41 |      S. Dakota  |
  42 |      Tennessee  |
  43 |          Texas  |
  44 |           Utah  |
  45 |        Vermont  |
  46 |       Virginia  |
  47 |    W. Virginia  |
  48 |     Washington  |
  49 |      Wisconsin  |
  50 |        Wyoming  |
     +-----------------+

There are plenty of ways to get a listing, e.g.

egen tag = tag(country)
list country if tag, noobs

But I'm still broadly at a loss to know what you want. If you explained why you want it, there could be better answers.