(myfactor.try1)
str(myfactor.try2)
Prof Brian Ripley [EMAIL PROTECTED] wrote: The behaviour has been changed in
the R-devel version of R, so the 'by'
columns are not converted to factors.
On Tue, 31 Jul 2007, Thomas Pujol wrote:
I have a two question regarding the aggregate.data.frame method
I have a two question regarding the aggregate.data.frame method of the
aggregate function.
My situation:
a. My x variable is a data.frame (mydf) with two columns, both columns of
type/format numeric.
b. My by variable is a data.frame(mybys) with two columns, both columns of
type/format
FYI, Here is a tip that Gabor Grothendieck sent to the r-com help-list.
Thought others might find it helpful.
http://mailman.csd.univie.ac.at/pipermail/rcom-l/2007-July/001717.html
Subject: Re: [Rcom-l] running Excel/Visual Basic macro from within R[input]
[input] [input]
I am trying to save an R data.frame as an Excel sheet.
I do NOT want the column names saved into row 1.
I set colnames=F.
However, it still seems that the colnames are saved into row 1.
Is this a bug? Or am I coding incorrectly and.or misunderstanding this feature?
#example code:
sheet =
Is there an easy or good way to run/launch an Excel VBA macro from within R?
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R-help@stat.math.ethz.ch
) if(fn.count(x)==0) NA else
t.test(x)$statistic) }
myfn.p.val - function(df) { apply(df,2,function(x) if(fn.count(x)==0) NA else
t.test(x)$p.value) }
Uwe Ligges [EMAIL PROTECTED] wrote:
Thomas Pujol wrote:
I have a dataframe (mydf) that contains differences of means.
I wish to test whether
I have a dataframe (mydf) that contains differences of means.
I wish to test whether these differences are significantly different from zero.
Below, I calculate the t-statistic for each column.
What is a good method to calculate/look-up the p-value for each column?
I often need to combine data frames, sometimes vertically and other times
horizontally.
When it better to use merge? When is it better to use rbind or cbind?
Are there clear pros and cons of each approach?
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I've read that certain operations performed on a matrix (e.g. ribind, cbind)
are often much faster compared to operations performed on a data frame.
Other then the bind functions, what are the main operations that are
significantly faster on a a matrix?
I know that data frames allow for
I have been trying to learn the various apply functions but am still learning
their appropriate use. I appreciate any help the R community can offer me.
Sorry for the length of this post.
Background:
I have data on my hard drive organized in the following manner:
The data pertains to many
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