Re: [R] Summary Statistics for data.frame

From: justin rapp <>
Date: Sun 09 Jul 2006 - 06:55:40 EST

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:

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?


On 7/8/06, Duncan Murdoch <> 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
> mailing list PLEASE do read the posting guide! Received on Sun Jul 09 06:59:22 2006

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