RE: st: construct a loop

[Nikolaos Pandis <npandis@yahoo.com>]

Dear Nick,

Many Thanks.

Best wishes

Nick


--- On Mon, 2/21/11, Nick Cox <n.j.cox@durham.ac.uk> wrote:

> From: Nick Cox <n.j.cox@durham.ac.uk>
> Subject: RE: st: construct a loop
> To: "'statalist@hsphsun2.harvard.edu'" <statalist@hsphsun2.harvard.edu>
> Date: Monday, February 21, 2011, 9:01 PM
> The help for -egen, group()- tells
> you about its -label- option. You really could have looked
> at that first! 
> 
> foreach v in var1 var2 var3 { 
>     egen group=group(`v')
>     sum group, meanonly
>     forval i = 1/`r(max)' {
>         di "`v': `: label
> (group) `i''" 
>         stmh hivstatus if
> group ==`i'
>     }
>     drop group 
> } 
> 
> is my guess at the other question. See -help extended_fcn-
> for the -label- stuff. 
> 
> Nick 
> n.j.cox@durham.ac.uk
> 
> 
> Nikolaos Pandis
> 
> Dear Nick,
> 
> Thank you. 
> 
> ********************
> egen group=group(age_cat gender)
> 
> sum group  ,meanonly
> 
> foreach i of num 1/`r(max)' {
> stmh hivstatus if group ==`i'
> }
> **************************
> 
> 
> I have added another variable and I get 6 combinations
> since age_cat has 3 levels (0,1,2) and gender 2 (0,1). 
> Should I assume that the sequence of the combinations is:
> age_cat:gender 00 01 10 11 20 21? 
> Could we label them?
> 
> Also, what if I do not want the combinations but rather to
> run the same code below for a number of variables
> separately.  
> 
> ********************
> egen group=group(var1)
> 
> sum group  ,meanonly
> 
> foreach i of num 1/`r(max)' {
> stmh hivstatus if group ==`i'
> }
> 
> egen group=group(var2)
> 
> sum group  ,meanonly
> 
> foreach i of num 1/`r(max)' {
> stmh hivstatus if group ==`i'
> }
> 
> 
> egen group=group(var3)
> 
> sum group  ,meanonly
> 
> foreach i of num 1/`r(max)' {
> stmh hivstatus if group ==`i'
> }
> 
> ect
> **************************
> How would I be able to consolidate the above 3 pieces of
> code into 1?
> 
> Many thanks,
> 
> Nick
> 
> 
> --- On Mon, 2/21/11, Nick Cox <n.j.cox@durham.ac.uk>
> wrote:
> 
> > From: Nick Cox <n.j.cox@durham.ac.uk>
> > Subject: RE: st: construct a loop
> > To: "'statalist@hsphsun2.harvard.edu'"
> <statalist@hsphsun2.harvard.edu>
> > Date: Monday, February 21, 2011, 8:12 PM
> > This too is covered in the FAQ just
> > cited. 
> > 
> > "It extends easily to the apparently much more
> difficult
> > problem of going through all the distinct combinations
> of
> > two or more variables, which is, in fact, only a
> little more
> > difficult. 
> >     . egen group = group(varlist)
> > 
> > Now the code is exactly the same as before. That is,
> > instead of one varname, you just need to spell out a
> varlist
> > in the argument to egen."
> > 
> > Nick 
> > n.j.cox@durham.ac.uk
> > 
> > 
> > Nikolaos Pandis
> > 
> > 
> > Thank you. I came up with the following code:
> > 
> > *********************
> > egen group=group(age_cat)
> > 
> > sum group  ,meanonly
> > 
> > foreach i of num 1/`r(max)' {
> >  stmh hivstatus if group ==`i'
> > }
> > ****************
> > 
> > How could I make this to do the same thing for other
> > variables such as age_cat?
> > 
> > 
> > --- On Sun, 2/20/11, Nick Cox <njcoxstata@gmail.com>
> > wrote:
> > 
> > > Well, your solution then gets more
> > > complicated. The thread has already
> > > shown that you can nest loops. Also see
> > > 
> > > FAQ     . . . . . . . . . . Making
> > > foreach go through all values of a variable
> > >         . . . . . . . . . . . . . . . .
> > > . . . . . . . . . . . . . .  N. J. Cox
> > >         8/05    Is there a
> > > way to tell Stata to try all values of a
> > >                
> > > particular variable in a foreach statement
> without
> > >                
> > > specifying them?
> > >                 http://www.stata.com/support/faqs/data/foreach.html
> > > 
> >  
> > > On Sat, Feb 19, 2011 at 8:48 PM, Nikolaos Pandis
> > <npandis@yahoo.com>
> > > wrote:
> > > 
> > > > Thank you all this looks great!
> > > >
> > > > Now what if I would like to run the same
> commands
> > for
> > > more than just the varX variable?
> > > > What if the variables have variable number
> of
> > category
> > > levels?
> > > >
> > > > Many thanks,
> > > >
> > > > Nick
> > > >
> > > >
> > > >
> > > > --- On Sat, 2/19/11, Nick Cox <njcoxstata@gmail.com>
> > > wrote:
> > > >
> > > >> From: Nick Cox <njcoxstata@gmail.com>
> > > >> Subject: Re: st: construct a loop
> > > >> To: statalist@hsphsun2.harvard.edu
> > > >> Date: Saturday, February 19, 2011, 9:14
> PM
> > > >> Here is another way to do it.
> > > >>
> > > >> foreach p in "1 0" "2 0" "3 0" "2 1" "3
> 1" "3
> > 2"
> > > {
> > > >> tokenize "`p'"
> > > >> stmh varX, c(`1' , `2')
> > > >> }
> > > >>
> > > >> Nick
> > > >>
> > > >> On Sat, Feb 19, 2011 at 12:03 PM,
> Nikolaos
> > Pandis
> > > <npandis@yahoo.com>
> > > >> wrote:
> > > >>
> > > >> > I would like to run the following
> > commands
> > > using the 4
> > > >> level varX:
> > > >> > stmh varX,c(1,0)
> > > >> > stmh varX,c(2,0)
> > > >> > stmh varX,c(3,0)
> > > >> > stmh varX,c(2,1)
> > > >> > stmh varX,c(3,1)
> > > >> > stmh varx,c(3,2)
> > > >> >
> > > >> > I would grateful if someone would
> help
> > me
> > > construct a
> > > >> loop to run all the above commands.
> 
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