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Re: st: foreach and globals and {.}


From   "Michael Blasnik" <michael.blasnik@verizon.net>
To   <statalist@hsphsun2.harvard.edu>
Subject   Re: st: foreach and globals and {.}
Date   Mon, 11 Apr 2005 07:21:05 -0400

The ${} are used to make the name of a global macro explicit to Stata when the context would otherwise make it unclear -- primarily when you want to embed a global macro name in a text string:

di "abc${myglobal}def"

allows Stata to figure out that the global macro is called myglobal. In the original pos, they don't need that syntax.

Michael Blasnik
michael.blasnik@verizon.net

----- Original Message ----- From: "Ulrich Kohler" <kohler@wz-berlin.de>
To: <statalist@hsphsun2.harvard.edu>
Sent: Monday, April 11, 2005 7:04 AM
Subject: Re: st: foreach and globals and {.}



Hans J. Baumgartner wrote:
Dear statalist,

has anybody an idea how to solve the following problem?


foreach x in ${out_`year’} {
do something
}

That is: I have several globals and I need the braces to tell Stata that
the local `year’ actually belongs to the global name.

Now I would like to run a loop over all elements in the global
${out_`year’}.

But the foreach command gets puzzled with the braces around the global,
since it thinks that this means to start the loop. And this returns an
error that a code follows on the same line as open braces.
I don't understand why you need the braces in ${out_`year'}. If $out_`year'
is a string, consisting out of several elements,

foreach x in $out_`year' {
do something
}

would be fine. If $out_`year' refers to a single element, which changes
according to `year' within a loop, I cannot see why you start a loop at all.

(I must admit that I have never seen something like ${out_`year'}, and I was
kind of surprised that

. global x "test"
. di "${x}"
test

works. Can anybody tell me what that means?)

uli
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