R help - May 2002 - Inputting Co-ordinates

Hello

I am trying to input some co-ordinate sets into R of the form x,y by using
lists.  The command I am using is:

p1 <- list(x=c(3445,563,646), y=c(234,567,456))

However the actual co-ordinate sets that I am trying to input have 305
points each and I think that the program will not accept a command that is
as long as necessary.  Is this so?  If this is the case can you tell me how
to read the points in as a table but so that I can call on them as being p1,
later in the program?

Many Thanks
Louise

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> Hello
>
> I am trying to input some co-ordinate sets into R of the form x,y by
using
> lists.  The command I am using is:
>
> p1 <- list(x=c(3445,563,646), y=c(234,567,456))
>
> However the actual co-ordinate sets that I am trying to input have 305
> points each and I think that the program will not accept a command
that is
> as long as necessary.  Is this so?  If this is the case can you tell
me how
> to read the points in as a table but so that I can call on them as
being p1,
> later in the program?
>
> Many Thanks
> Louise
One easy way is to enter the coordinates into a text file with a text
editor so that the file looks like:

x y
3445 234
563 567
646 456
...

and then read into R with a statement

p1 <- read.table ("file.name", header=TRUE)



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Go to http://lib.stat.cmu.edu/R/CRAN/, click on the "Manual" link on 
the left, and get two of the documents:

An Introduction to R (approx. 100 pages, 650kB), based on the former 
"Notes on R", gives an introduction to the language and how to use R 
for doing statistical analysis and graphics.

R Data Import/Export (approx. 30 pages, 270kB) describes the import 
and export facilities available either in R itself or via packages 
which are available from CRAN.

Briefly, put your coordinates in a plain text file (two columns, x 
and y, similar to a spreadsheet), and use the scan() function to read 
them in from the file.

-Don

At 4:53 PM +0100 5/8/02, Louise Cox wrote:
>Hello
>
>I am trying to input some co-ordinate sets into R of the form x,y by using
>lists.  The command I am using is:
>
>p1 <- list(x=c(3445,563,646), y=c(234,567,456))
>
>However the actual co-ordinate sets that I am trying to input have 305
>points each and I think that the program will not accept a command that is
>as long as necessary.  Is this so?  If this is the case can you tell me how
>to read the points in as a table but so that I can call on them as being p1,
>later in the program?
>
>Many Thanks
>Louise
>
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>r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
>Send "info", "help", or "[un]subscribe"
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-- 
--------------------------------------
Don MacQueen
Environmental Protection Department
Lawrence Livermore National Laboratory
Livermore, CA, USA
--------------------------------------
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Louise,
  See answer below:
> 
> I am trying to input some co-ordinate sets into R of the form x,y by using
> lists.  The command I am using is:
> 
> p1 <- list(x=c(3445,563,646), y=c(234,567,456))
> 
> However the actual co-ordinate sets that I am trying to input have 305
> points each and I think that the program will not accept a command that is
> as long as necessary.  Is this so?  If this is the case can you tell me how
> to read the points in as a table but so that I can call on them as being
p1,
> later in the program?
Why not just place the points in a text file? E.g.

x, y
3445, 234
563, 567
646, 456

Save the last four lines into a text file called `coords.csv' (no
quotes).

In R, use the commands:
> p1 <- read.csv("coords.csv",header=T)
> p1
     x   y
1 3445 234
2  563 567
3  646 456
> p1$x
[1] 3445  563  646
> p1$y
[1] 234 567 456
> p1.list <- as.list(p1)
> p1.list
$x
[1] 3445  563  646

$y
[1] 234 567 456
> 
See read.csv or read.table for more details.

Sundar

-- 

Sundar Dorai-Raj, Ph.D.
Statistical Methods Engineer
PDF Solutions, Inc.
Richardson TX
(972) 889-3085 x216
(214) 392-7619 cell
sundar.dorai-raj at pdf.com
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