st: Re: statalist-digest V4 #1868

[Mike Lacy <Michael.Lacy@colostate.edu>]

I am wanting to use -predict- after -ologit- to put the predicted 
probabilities into a set of temporary variables.  I think my questions may 
bring up enough issues about using temporary variables so as to be of more 
general interest.

Questions:

1) How to use -predict- to store values in a list of tempvars .

Example:

use auto.dta
ologit rep78 price turn
local k = `e(k_cat)'  /* save for future use
local ptop = "p`k'"
predict p1-`ptop'

This works fine, but what I would really like is to
get the predicted probabilities into a list of *tempvars.*
   tempvar p1-`ptop'
is apparently not legal syntax.

So, I put all the the p1, ..., pk into a local macro, say plist,
using run time information about k, so I get plist = "p1 p2 p3 ... pk"

Then, I find that
   tempvar `plist'
creates the list of temporary variables as desired,
but then I can't figure how to use `plist' to -predict-
the list of probabilities into the tempvars in plist.

So, what would be recommended as a way to get
a vector of predicted probabilities into a
list of tempvars? Perhaps my `plist' *can* be used?


2) Next, I have occasion to use these tempvars in loops.

As a simplifed,idealized code fragment to illustrate a confusion
I have experienced, consider

tempvar x1 x2 x3
foreach x of varlist `x1'-`x3' {
   gen `x' = rand()
}

This generates an error message indicating that one of the
temporary variables is "not found", unless I assign values
to each of `x1'-`x3' by brute force prior to running the loop and then do a 
-replace- rather than -gen- in the loop.

Clearly, I am missing some piece of understanding here as well.
I guess the question would be:
How to use a list of temporary variables in a loop if those temporary 
variable do not yet have assigned values?

Regards,

=-=-=-=-=-=-=-=-=-=-=-=-=
Mike Lacy
Fort Collins CO USA
(970) 491-6721 office





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