[R] array vs matrix vs dataframe?

Duncan Murdoch murdoch at stats.uwo.ca
Mon Oct 2 02:35:38 CEST 2006


On 10/1/2006 7:02 PM, r user wrote:
> What is the difference among an array, a dataframe and
> a matrix?

Really, r, I think this is pretty well documented.  Could you let us 
know what you've read that left this ambiguous?

> 
> Why is the size of a dataframe so much larger? (see
> example below)

I suspect it's the row names.

Duncan Murdoch

> 
> a<-c(rep(1:1000000,1))
> b<-c(rep(1:1000000,1))
> c1<-cbind(a,b)
> cdf<-as.data.frame(cbind(a,b))
> cm<-as.matrix(cbind(a,b))
> 
> object.size(a)/1000000
> object.size(b)/1000000
> object.size(c1)/1000000
> object.size(cdf)/1000000
> object.size(cm)/1000000
> 
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