[S] using strings for formula in ms()

Kristian S. Gleditsch (ksg@cfia.harvard.edu)
Thu, 20 Aug 1998 00:47:05 -0400


Dear S-news'ers,

I have a fairly lengthy equation that I want to minimize with ms() inside a
generic function I am writing

I would like to create the formula corresponding to a set of right hand
side variables in a character vector

(e.g., xxx.formula <- c("log(1-lambda*wroot),
paste("+lambda*b",1:(length(betas)-1),"*",sep="",...")

with the different variables and parameters used all in a dataframe

(e.g. xxx.data).

However, I am unable to use this character vector as the formula in ms, e.g.

ms(~xxx.formula,data=xxx.data)

Must I convert the vector to some other mode or class, or is there any
other way to get this to work?

Any help and suggestions would be much appreciated!

Sincerely,
Kristian Gleditsch

---------------------------------
Kristian S. Gleditsch
Fellow, Harvard-MIT Data Center, Ph.D. Candidate, U. of Colorado
Mailing address: Weatherhead Center for International Affairs
1737 Cambridge St., Room 416A, Cambridge, MA 02138
tel: (617) 495-9876, fax: (617) 495-8292, ksg@cfia.harvard.edu
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