Paul et. al:
I think Gabor's incantation qualifies as my desired alternative to
eval(parse())). It is, unfortunately, rather tricky, imo.
However, the objection you raise to the gsub(deparse()) solution is
easily overcome through the use of an appopriate regex: e.g.:
gsub("\\<x\\>","log(x)","x+xc+cx")
[1] "log(x)+xc+cx"
See the ?regex documentation on \< and \> . I believe this allows this
simple approach to handle all cases -- am I wrong about this?
Incidentally, I need to note that I was **wrong** in my previous statement that
formula(lm(y!x1)) does not work. It works fine, as there is a formula
method for (g)lm . I should look before I leap.
-- Bert
On Tue, May 29, 2012 at 10:41 AM, Paul Johnson <pauljoh...@gmail.com> wrote:
>>>
>>
>> Try substitute:
>>
>>> do.call("substitute", list(newFmla, setNames(list(as.name("x1c")), "x1")))
>> y ~ log(x1c) + x2 * x3
>>
> Damn. That's pretty. I'd say "setNames" a magic bullet too.
>
> Thanks very much.
>
> The approach suggested by Michael and Bert has the little shortcoming
> that grepping for "x1" also picks up similarly named variables like
> "x1new" and "x1old". I've not yet found a similar downside with
> Gabor's method.
>
> pj
>>
>> --
>> Statistics & Software Consulting
>> GKX Group, GKX Associates Inc.
>> tel: 1-877-GKX-GROUP
>> email: ggrothendieck at gmail.com
>
>
>
> --
> Paul E. Johnson
> Professor, Political Science Assoc. Director
> 1541 Lilac Lane, Room 504 Center for Research Methods
> University of Kansas University of Kansas
> http://pj.freefaculty.org http://quant.ku.edu
>
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--
Bert Gunter
Genentech Nonclinical Biostatistics
Internal Contact Info:
Phone: 467-7374
Website:
http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm
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