bind mean to a df
Hi, You could try, library(plyr) ddply(data, .(name), transform, mean=mean(sale)) ddply(data, .(name), summarize, mean=mean(sale)) HTH, baptiste
On 12 April 2011 15:46, Geoffrey Smith <gps at asu.edu> wrote:
Hello, I would like to take the mean of a column from a data frame and then
bind the mean back to the data frame. ?I can do this using the following
lines of code, but I am looking for a more elegant solution. ?Thank you very
much. ?Geoff
name <- c('Frank','Frank','Frank','Tony','Tony','Tony','Ed','Ed','Ed');
year <- c(2004,2005,2006,2004,2005,2006,2004,2005,2006);
sale <- c(56,45,55,65,68,70,45,67,23);
data <- data.frame(name=name, year=year, sale=sale);
data;
#is there a more elegant way to add a column of means for sale by name than
what I did below?;
mean <- data.frame(aggregate(data$sale, list(data$name), mean));
colnames(mean) <- c('name','mean');
mean;
data <- merge(data, mean);
data;
? ? ? ?[[alternative HTML version deleted]]
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