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Re: st: Re: two questions about matrix operations

From   Ulrich Kohler <[email protected]>
To   [email protected]
Subject   Re: st: Re: two questions about matrix operations
Date   Thu, 6 Jan 2005 15:30:02 +0100

Katsuhide Isa wrote:
> As to the 1st question, when I ran the following,
> >foreach var of varlist A-D{
> >	count if `var' == 0
> >	local sum = `sum' + r(N)
> > }
> >di `sum'
> following error messages are shown:
> Unknown function +r()
> r(133);

The problem is, that the local macro `sum' isn't defined in the first round of 
the loop. 

local sum 0
foreach var of varlist A-D {
	count if `var' == 0
	local sum = `sum' + r(N)
di `sum'

should work. This is nicer than your solution in that you save one command 
inside the loop. However with just four loops this will not make any 

> But this time, after numbers of zeros for each variable and
> total sum of zeros are vertically shown, following error
> messages appear:
> # The same messages are shown after running the statements
> pertaining to the 2nd question.
> no; data in memory would be lost
> r(4);

This message does not stem from the snippet above.  If you load several files 
in a loop you should load them with -use filename, clear-. However it might 
be an idea to merge/append the files toghether before starting the analysis. 

many regards

[email protected]
+49 (030) 25491-361

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