[R] Strange result from single [] extract operator

Patrick Burns pburns at pburns.seanet.com
Sun Sep 29 10:47:09 CEST 2013


See Circle 8.1.3 of 'The R Inferno'.

http://www.burns-stat.com/documents/books/the-r-inferno/

Pat

On 28/09/2013 16:18, rafael.7 at poczta.fm wrote:
> Hi All,
>
> I am using Rx64 3.0.1 on Windows 7 x64, and wanted to get two last rows from dataset. First, I tried
>   library(datasets)
>> data<-airquality
>> data[nrow(data)-1:nrow(data),]
>
> and received 152 rows sorted desc. Could you explain why it worked this way? I changed the extract line to:
> data[(nrow(data)-1):nrow(data),]
>
> and then I received what I wanted but still am curious about the performance of my previous code.
>
> Yours faithfully,
> Rafał
>
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>

-- 
Patrick Burns
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