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Re: st: Levelsof for more than one Variable

From   Roberto Liebscher <>
Subject   Re: st: Levelsof for more than one Variable
Date   Mon, 21 Jan 2013 17:22:24 +0100

Thanks Maarten for the kind help. However I still haven't managed to get the code working.

Like you said I typed

levelsof var1, local(loc1)
levelsof var2, local(loc2)

// stack the macros
// NOTICE: no "=" sign
local loc "`loc1' `loc2'"

// get rid of the duplicates
local loc : list uniq loc

But when I type

display "`loc'"

to get the final list an error message is prompted saying

`ABN not found

where ABN is part of the first element of loc1 ("ABN Amro Bank"). Is it a problem that my elements in the list contain blank spaces? Is there a way around? I already tried the same code with the blank space being replaced by "_" (using subinstr). Following this another error message pops up saying "`unknown function ABN_AMRO_Bank_N.V."' `"BNP_Paribas"'" . I do not know what is wrong here. Any help is highly appreciated.


Roberto Liebscher
Catholic University of Eichstaett-Ingolstadt
Department of Business Administration
Chair of Banking and Finance
Auf der Schanz 49
D-85049 Ingolstadt

Am 21.01.2013 15:52, schrieb Nick Cox:
As a kind of meta-comment I recommend against the use of "unique" in
this context.

"Unique" means occurring once only. It's a good word, and best left to
mean that, as your school teachers may have urged. For example,
"StataCorp is a unique company". Very true (if also trite).

Naturally, some might want to start the age-old discussion of whether
usage sanctifies abuse of etymology.  But even descriptively-inclined
dictionaries don't seem to sanction the sense of this word "unique" as
meaning "distinct", which I suggest is a much better word than
"unique" for this purpose.

My guess is that the popularity of "unique" in this meaning stems
partly from Unix utilities such as -uniq-, which removes copies from a
list and leaves one and one copy of each distinct item as a result.

a a a b b c

would be reduced to

a b c

by such utilities.

Here uniqueness defines each item in the result, not each item in the
argument. My guess is that many software developers encountered such
utilities such as -uniq- in their youth and that had a greater
influence on them than their English dictionaries (if they had one) or
their English teachers (if they paid them much attention).

I have a long-term plan to persuade StataCorp of this too. See also

SJ-8-4  dm0042  . . . . . . . . . . . .  Speaking Stata: Distinct observations
         (help distinct if installed)  . . . . . .  N. J. Cox and G. M. Longton
         Q4/08   SJ 8(4):557--568
         shows how to answer questions about distinct observations
         from first principles; provides a convenience command

I can't speak authoritatively on languages other than English -- "not
even", some might think -- so not mentioning them means only that.


On Mon, Jan 21, 2013 at 2:30 PM, Maarten Buis <> wrote:
// collect the values
levelsof var1, locals(loc1)
levelsof var2, locals(loc2)

// stack the macros
// NOTICE: no "=" sign
local loc "`loc1' `loc2'"

// get rid of the duplicates
local loc : list uniq loc

For more see: -help extended_fcn- and especially -help macrolists-

Hope this helps,

On Mon, Jan 21, 2013 at 3:02 PM, Roberto Liebscher
<> wrote:
I have two variables both containing string values. I would like to get all
unique values (not the number of unique values) from these two variables

For example if I enter

levelsof var1, locals(loc1)
levelsof var2, locals(loc2)

I obtain all unique values of var1 and all unique values of var2. But at the
end I would like to have one local containing only unique values in loc1 AND

Is there anyone who can help me with this?
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