On Oct 23, 2010, at 6:56 PM, Gabor Grothendieck wrote:
On Sat, Oct 23, 2010 at 9:51 PM, James Hirschorn
<james.hirsch...@hotmail.com> wrote:
What is a good way to enter a very long model formula. For example:
y ~ Input.2 + Input.3 + ... + Input.1000
(assuming the corresponding dataframe has many other columns).
Is there a way to convert a character string to a formula? Are
there command line expansions in R besides the simple '.'?
If y is in column 1 and Input.2, ..., Input.1000 are in columns 2
through 1000 then try this:
lm(y ~., DF[1:1000])
I guess the next logical(?) question would be: If the independent
variables of interest are in columns 3,5,6,7,8,9,10,and 13 and the
dependent variable is in column 20, would this work:
lm(y ~., data=DF[c(20, 3,5,6:10, 13)])
# ? with any consecutive columns specified with the ":" operator?
Or perhaps with grep("patt") in with the column indices?
--
David.
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