[R] Calculate Mean of Column Vectors?

[Mulholland, Tom]

apply(y,2,mean)

Is this what you are after. If it is I would suggest that you look at the examples not just for this but for what I call the apply family sapply, tapply, mapply. Once you get the hang of these they are really helpful.

Tom.

> -----Original Message-----
> From: Thomas Hopper [mailto:thopper106035 at comcast.net]
> Sent: Tuesday, 11 January 2005 11:46 AM
> To: r-help at stat.math.ethz.ch
> Subject: [R] Calculate Mean of Column Vectors?
> 
> 
> Hello,
> 
> I've got an array defined as y <- rnorm(3000), dim(y) <- c(3, 1000).
> 
> I'd like to produce a 1000-element vector z that is the mean of the 
> corresponding elements of y (like z[1,1] <- mean(y[1,1], y[2,1], 
> y[3,1])), but being new to R, I'm not sure how to do this for all 
> elements at once (or, at least, simply). Any help is appreciated.
> 
> Thanks,
> 
> Tom
> 
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