[R] re shape package - use one cast() instead of many
h.wickham at gmail.com
Tue May 5 22:20:03 CEST 2009
On Tue, May 5, 2009 at 3:03 PM, jwg20 <jason.gullifer at gmail.com> wrote:
> I have a data set that I'm trying to melt and cast in a specific way using
> the reshape package. (I'll use the ff_d dataset from reshape so I don't have
> to post a toy data set here. )
> Lets say I'm looking for the interaction of treatment with each type of
> "variable" in ff_d. Using the command below gets me this. Subject will get a
> column and each treatment type by each variable will also get a column with
> values for each.
> cast(ff_d, subject~treatment+variable)
> subject 1_potato 1_buttery 1_grassy 1_rancid 1_painty 2_potato 2_buttery
> .... 3_painty
> 1 3 18 18 18 18 18 18 18
> .... 18
> Now, if I want to look at just the the values for each variable by subject
> I can run the following command.
> cast(ff_d, subject~variable)
> subject potato buttery grassy rancid painty
> 1 3 54 54 54 54 54
> What I'm wondering now, is run one cast() call and get both of these in one
> data.frame? Essentially, the values for each separate "condition" and
> interactions between them? cast() doesn't let me repeat variable names as
> that's what I first tried. Right now, i'm just running two separate cast()
> calls and cbinding/merging them together. Is there a better way?
Have a look at the margins argument.
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