When I attempt to use the mysummary function, I obtain the following error:
Error in var(x) : missing observations in cov/cor When I use: by(data.logistic,data.logistic$Ydrafted,summary) I receive no errors. I cut and pasted your mysummary function directly into my r console. Should I have made any adjustments to the code? jdr On 7/8/06, Duncan Murdoch <[EMAIL PROTECTED]> wrote: > On 7/8/2006 3:44 PM, justin rapp wrote: > > I apologize for my constant questions but I am new to R and trying to > > gain an appreciation for its capabilities. The following task is easy > > in Excel and I was hoping somebody could give me a quick explanation > > for how it can be acheived in R so I can avoid having to switch > > between the two applications. > > > > How do I find the Summary Statistics in one Vector of the dataframe by > > levels in another of the vectors. > > > > For example, I have the following headings for my data.frame. > > Conference > > Year Drafted > > Height > > Weight > > Ratio > > > > I would like to see compute the mean Height, Weight, and Ratio as well > > as their variances for each of the years under Year > > Drafted(1980-2000). What is the most efficient way of doing this? > > I think the quickest is > > by(mydf, mydf$Year, summary) > > but this won't give you the variance. You'll need your own little > function to calculate mean and variance, e.g. > > mysummary <- function(df) apply(df, 2, > function(x) c(mean=mean(x), variance=var(x))) > > by(mydf, mydf$Year, mysummary) > > If you don't like the format of the output, you can play around with the > mysummary function. It will be applied to each subset of the > data.frame, and the results will be put together into a list with one > entry per level of mydf$Year. > > > Duncan > ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html