> 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.
Back up a little and compare
nrow(data)-1:nrow(data)
to
(nrow(data)-1):nrow(data)
or compare
3-1:3
to
(3-1):3
Then look at the help file for "Syntax".
Bill Dunlap
Spotfire, TIBCO Software
wdunlap tibco.com
> -----Original Message-----
> From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On
> Behalf
> Of rafae...@poczta.fm
> Sent: Saturday, September 28, 2013 8:18 AM
> To: r-help@r-project.org
> Subject: [R] Strange result from single [] extract operator
>
> 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
>
> ______________________________________________
> R-help@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
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