[R] Splitting the left and right hand terms of a formula
Daniel Gerlanc
dgerlanc at gmail.com
Fri Jul 14 20:23:30 CEST 2006
Let's say I have the following formula:
a.formula <- x ~ y + z
I want to extract the left and right-hand sides of the function so
that I have two character vectors like the ones you would create using
the following assignments:
left.hand.side <- "x"
right.hand.side <- c("y", "z")
One way to do this follows:
left.hand.side <- unlist(dimnames(attr(terms(a.formula), "factors"))[1])
right.hand.side <- unlist(dimnames(attr(terms(a.formula), "factors"))[-1])
Is there a better or cleaner way to do this?
Thanks!
Daniel Gerlanc
Williams College '07
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