R help - Oct 2010 - keep adding elements to the matrix

Hello everyone,
I would like to create a "dynamic" array to keep storing number in it

for (i in c(2:length(final))){
    myarray <-final[i]-final[i-1]
    myarray2<-2*final[i]  
  }



At the end I would like to use myarray as the x values of an array
and the myarray2 as the yvalues of the same array.
I tried cbind but it didnot work.

Could you please help me with that?

Best Regards
Alex



      
	[[alternative HTML version deleted]]

Hello Alex.

I'm a bit confused by your english, but what I guess you want is:
x<-final[-1] - final[-length(final)]
y<-2*final[-1]

result<-cbind(x=x, y=y)

Good luck.


Nick Sabbe
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-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
On
Behalf Of Alaios
Sent: woensdag 27 oktober 2010 16:38
To: Rhelp
Subject: [R] keep adding elements to the matrix

Hello everyone,
I would like to create a "dynamic" array to keep storing number in it

for (i in c(2:length(final))){
    myarray <-final[i]-final[i-1]
    myarray2<-2*final[i]  
  }



At the end I would like to use myarray as the x values of an array
and the myarray2 as the yvalues of the same array.
I tried cbind but it didnot work.

Could you please help me with that?

Best Regards
Alex



      
	[[alternative HTML version deleted]]

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On Oct 27, 2010, at 10:37 AM, Alaios wrote:
> Hello everyone,
> I would like to create a "dynamic" array to keep storing number
in it
>
>
> for (i in c(2:length(final))){
>    myarray <-final[i]-final[i-1]
>    myarray2<-2*final[i]
>  }

Because there are no indices on the left hand side of those  
assignments, you are just overwriting those values. If you want  
myarray and myarray2 to actually be vectors, (or matrices or arrays),  
then you need to create them with the proper dimension(s) and then  
index them when assigning into  them.
>
> At the end I would like to use myarray as the x values of an array
> and the myarray2 as the yvalues of the same array.
Perhaps
myarray <- matrix(NA, nrow=length(final)-1, ncol=2)

myarray[ , 1] <- diff(final)
myarray[ , 2] <- 2*final[2:length(final)]

> I tried cbind but it didnot work.
>
> Could you please help me with that?
David Winsemius, MD
West Hartford, CT