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]]
Hi Geoffrey,
Here is one option (data named dfrm instead of data because data() is
a function too):
## Data
dfrm <- data.frame(
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))
## Using with() to avoid typing names and ave() to do the work
dfrm$mean <- with(dfrm, ave(x = sale, name, FUN = mean))
## look at the results
dfrm
Cheers,
Josh
On Mon, Apr 11, 2011 at 8:46 PM, Geoffrey Smith <gps at asu.edu>
wrote:> Hello, I would like to take the mean of a column from a data frame and then
> bind the mean back to the data frame. ?I can do this using the following
> lines of code, but I am looking for a more elegant solution. ?Thank you
very
> much. ?Geoff
>
> name <-
c('Frank','Frank','Frank','Tony','Tony','Tony','Ed','Ed','Ed');
> year <- c(2004,2005,2006,2004,2005,2006,2004,2005,2006);
> sale <- c(56,45,55,65,68,70,45,67,23);
>
> data <- data.frame(name=name, year=year, sale=sale);
> data;
>
> #is there a more elegant way to add a column of means for sale by name than
> what I did below?;
>
> mean <- data.frame(aggregate(data$sale, list(data$name), mean));
> colnames(mean) <- c('name','mean');
> mean;
>
> data <- merge(data, mean);
> data;
>
> ? ? ? ?[[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
--
Joshua Wiley
Ph.D. Student, Health Psychology
University of California, Los Angeles
http://www.joshuawiley.com/
Hi, You could try, library(plyr) ddply(data, .(name), transform, mean=mean(sale)) ddply(data, .(name), summarize, mean=mean(sale)) HTH, baptiste On 12 April 2011 15:46, Geoffrey Smith <gps at asu.edu> wrote:> Hello, I would like to take the mean of a column from a data frame and then > bind the mean back to the data frame. ?I can do this using the following > lines of code, but I am looking for a more elegant solution. ?Thank you very > much. ?Geoff > > name <- c('Frank','Frank','Frank','Tony','Tony','Tony','Ed','Ed','Ed'); > year <- c(2004,2005,2006,2004,2005,2006,2004,2005,2006); > sale <- c(56,45,55,65,68,70,45,67,23); > > data <- data.frame(name=name, year=year, sale=sale); > data; > > #is there a more elegant way to add a column of means for sale by name than > what I did below?; > > mean <- data.frame(aggregate(data$sale, list(data$name), mean)); > colnames(mean) <- c('name','mean'); > mean; > > data <- merge(data, mean); > data; > > ? ? ? ?[[alternative HTML version deleted]] > > ______________________________________________ > R-help at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. >