averaging pairs of columns in a dataframe
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 <jonathan.denniss at googlemail.com> wrote:
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 to use rowMeans but have not been able to average the pairs of columns, only the whole dataframe. Any help would be appreciated, I am new to R. Thanks in advance, Jon. -- View this message in context: http://www.nabble.com/averaging-pairs-of-columns-in-a-dataframe-tp19181319p19181319.html Sent from the R help mailing list archive at Nabble.com.
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