Re: st: using varlist wildcards in anova

[Phil Schumm <pschumm@uchicago.edu>]

On Apr 3, 2010, at 6:25 PM, Phil Schumm wrote:
> On Apr 3, 2010, at 5:45 PM, Vineet Bhagwat wrote:
> > Which is weird, because on my computer's Stata, "reg y t* " and any  
> > other command using the asterisk works fine, just -anova- that  
> > seems to throw the error for some reason.  I'm using Stata9 on my  
> > computer if that clarifies anything.
>
>
> Well, at least that narrows it down.  I no longer have a version of  
> Stata 9 on my machine, so I can't look at this issue further.   
> Perhaps someone with Stata 9 still available (or a better memory of - 
> anova- under version 9) might be able to add something.
>
> One workaround would be the following (IIRC, -unab- predated Stata 9):
>
>    unab t: t*
>    anova y `t'
>
> though upgrading, if possible, would clearly be preferable.


Ok, I must confess that this made me a bit curious, especially since  
my previous statement


On Apr 3, 2010, at 5:21 PM, Phil Schumm wrote:
> Regardless, this isn't due to -anova-, but rather is a function of  
> how Stata is parsing the command line.


was clearly incorrect (I also misspoke when I said "parsing the  
command line" -- what I should have said was "expanding the  
varlist").  Instead, this *does* have to do with -anova-'s syntax.  I  
pulled an old copy of Stata 9, and sure enough, I get exactly the  
behavior Vineet describes.

Unfortunately, in Stata 9 -anova- was a built-in command, so we can't  
look at the source.  However, the syntax diagram

    anova varname [term [/] [term [/] ...]] [if] [in] [weight] [,
          options]

    where term is of the form   varname[{*||}varname[...]]

suggests that -anova- was using its own approach to interpret the list  
of model terms, and although one could specify a model as a simple  
list of variables, -anova- under Stata 9 evidently didn't support  
varname globbing.

In sum, the workaround I gave above is your only option under Stata 9.


-- Phil

*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/