somehow robust method for dataframe df would be
newdf - (df[,seq(1,66,2)]+df[,seq(2,66,2)])/2
Gasper
-Original Message-
From: JonD [mailto:[EMAIL PROTECTED]
Sent: Wednesday, August 27, 2008 3:47 PM
To: r-help@r-project.org
Subject: [R] averaging pairs of columns in a dataframe
Dear all,
I have a dataframe with 132 columns and 100 rows. Every 2nd column is a
repeat measurement so that the columns could be titled, a a b b c c d d etc.
I would like to average the repeats such that I am left with a data frame of
66 columns (of means) and 100 rows.
I have been trying
Try this:
# test data
DF - data.frame(a = 1:9, a = 21:29, b = 31:39, b = 41:49, check.names = FALSE)
t(apply(DF, 1, tapply, names(DF), mean))
It gives a matrix so use as.data.frame on that if you need a data frame
On Wed, Aug 27, 2008 at 9:47 AM, JonD [EMAIL PROTECTED] wrote:
Dear all,
I
That's great, thanks!
Jon
Gabor Grothendieck wrote:
Try this:
# test data
DF - data.frame(a = 1:9, a = 21:29, b = 31:39, b = 41:49, check.names =
FALSE)
t(apply(DF, 1, tapply, names(DF), mean))
It gives a matrix so use as.data.frame on that if you need a data frame
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