Dear R-Helpers
Given a function like
foo <- function(data,var1,var2,var3) {
f <- formula(paste(var1,'~',paste(var2,var3,sep='+'),sep=''))
linmod <- lm(f)
return(linmod)
}
By typing
foo(mydata,'a','b','c')
I get the result of the linear model a~b+c.
How can I rewrite the function so that the formula can be updated inside
the function, i.e.
foo <- function(data,var1,var2,var3,var4) {
f <- formula(paste(var1,'~',paste(var2,var3,sep='+'),sep=''))
linmod <- lm(f)
return(linmod)
f2 <- update.formula(f,.~.-var3+var4)
}
Like that it won't work because var3 and var4 are characters, but also
with substitute() and eval() I did not manage to get the favoured result.
Can somebody help me out?
Thank you in advance
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