[R] Anyone can help with this question

[David Winsemius]

On Nov 16, 2010, at 12:13 PM, Mariana wrote:

>
> Hi there:
> I am a total beginner in R,

Time to read the Posting Guide. (Especially since Nabble appears to  
deficient in providing an introductory document, at least judging from  
the email behavior of some of its users.)

> and I have a simple question:
> I have a table with thousands of lines that represent locations, and  
> two
> columns: latitude and longitude. I need to randomly sample 1000  
> lines. How
> do I do it? I know the command "sample", but it samples elements
> independently, not lines.

So use that vector as an index:

latlong.tbl[ sample(NROW(latlong.tbl), 1000) , ]

# should work for matrices or dataframes or table objects

> If there is a better place for me to ask that type of question,  
> please let
> me know.
> Thanks a lot,
> Mariana (from Brazil)


-- 
David Winsemius, MD
West Hartford, CT