Forget eval(parse(text = ))
See
?as.formula
?update.formula
and try out the example() s there.
HTH,
Chuck
On Mon, 16 Feb 2009, Crouch, Daniel wrote:
Hi,
I am having difficulty entering a 'programmable' argument into the multinom
function from the nnet package. Interactively, I can get the function to work
fine by calling it this way:
z1=multinom(formula = class.ind(grp[-outgroup])~ (PC1 + PC2 + PC3),
data=data.frame(scores))
However I need to be able to change the number of variables I am looking for in
'scores' and so am trying to call it this way...
z1=multinom(formula = class.ind(grp[-outgroup])~ eval(parse(text=PCnames)),
data=data.frame(scores))
...where, for example, PCnames = c("PC1", "+", "PC2", "+", "PC3")
This gives no error messages, but only the last variable (in this case PC3)
gets considered in the model. z1 looks like this:
(Intercept) eval(parse(text = PCnames))
2 3.530352 -116.87140
3 -1.308613 13.59134
4 3.662172 -57.52198
5 -1.216041 -242.38827
6 -9.377894 -367.71614
7 -3.145738 -286.19766
Rather than this:
(Intercept) PC1 PC2 PC3
2 288.97131 889.281 3776.5837 -2105.751
3 -712.53519 2775.663 8490.5724 8602.834
4 229.17772 4234.950 329.6995 -2182.238
5 85.54585 -3036.657 3968.2517 -3450.070
6 -676.55377 -9545.785 2422.5340 -7183.686
7 -631.91921 10997.432 -3310.2905 -5348.513
Any help would be much appreciated.
Thanks,
Daniel Crouch
Daniel Crouch
Research Student
Department of Medical & Molecular Genetics
King's College London
8th Floor, Tower Wing
Guy's Hospital
London SE1 9RT
United Kingdom
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
Charles C. Berry (858) 534-2098
Dept of Family/Preventive Medicine
E mailto:cbe...@tajo.ucsd.edu UC San Diego
http://famprevmed.ucsd.edu/faculty/cberry/ La Jolla, San Diego 92093-0901
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
