At 05:43 PM 7/25/2005 +0200, Thomas Cornelissen wrote:
Dear Stata Users,
I want to write an ado file using the -syntax- command as follows:
syntax varlist(min=2) [if] [in]
The first variable in varlist is the dependent variable, the others are
the independent variables. I need to access them seperately in my ado-file.
Therefore I create a local that contains the name of the dependent
variable, i.e. the first word of the varlist-string, and a local that
contains all the rest and can be used as a varlist of only the independent
variables.
local depvar=word("`varlist'",1)
local indepvar=substr("`varlist'",length("`depvar'")+1,length("`varlist'"));
My problem is that if the varlist is very long, it gets cut off at the
81st character. It seems that both the -length- and the -substr- function
can only be applied to strings up to 81 characters.
I tried also to precede 'varlist' in the -syntax- command by 'varname',
'name' or 'anything' to capture the independent variable, but that returns
error messages.
Can anybody suggest a better way to do what I want to do? Is there a good
way of splitting one varlist into two varlists?
Thanks a lot for any suggestions!
Thomas
------------------------------------------------------------------
Thomas Cornelissen
Empirical Economic Research
University of Hannover, Germany
The problem is that you are setting the macros to expressions -- using an
equal sign. String expressions are limited to 80 characters (or something
longer in Stata SE).
If instead, you use extended functions, this truncation will not occur (at
least, not for a few thousand characters). You should look into the macro
extended functions. See -help local-, and loot at the "extended_fcn"
section. Often, a function also exists as an extended function for macros,
and you can just switch the = to a : (colon) -- though sometimes the syntax
is a bit different (as shown below).
But in your case, there are possibly better options.
local depvar : word 1 of "`varlist'"
/* Note the colon and the somewhat different syntax. You had local
depvar=word("`varlist'",1), which is probably okay, because of the length
of a variable name, but this is, generally, more secure.
*/
local indepvar : list varlist - depvar
/* -- gets you what you want directly. See -help macrolists-.
There are other solutions, but this is probably the simplest in terms of
programming, and it is very comprehensible.
*/
HTH,
-- David
David Kantor
Institute for Policy Studies
Johns Hopkins University
[email protected]
410-516-5404
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