[R] pass lm( ) a char vector as the variables to be included

[boshao zhang]

Dear Everyone in list:
I am writing some codes to automate the process of
fitting linear models where the names of variables of
models are produced and stored in character vectors.
But I have problems to pass the vectors to the lm( )
because I don't know how to strip the quotation marks
automatically. 

Here are the codes of the example of lm( ):

## Annette Dobson (1990) "An Introduction to
Generalized Linear Models".
## Page 9: Plant Weight Data.
ctl <-
(4.17,5.58,5.18,6.11,4.50,4.61,5.17,4.53,5.33,5.14)
trt <-
(4.81,4.17,4.41,3.59,5.87,3.83,6.03,4.89,4.32,4.69)
group <- gl(2,10,20, labels=c("Ctl","Trt"))
weight <- c(ctl, trt)
anova(lm.D9 <- lm(weight ~ group))
lm.D90 <- lm(weight ~ group - 1) # omitting intercept

What I am doing is let the variable name "group"
stored in a vector, say, g <- "group". The question is
how to strip the quotation marks when we call lm( )
through g?

Thank you all.

Boshao



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