Dear All,

thank you for all answers. First answer helped me understand the
performance of code better, second showed me how to solve the problem
easier and third provided me with interesting pdf to learn.

I am very grateful for your help.

Best regards,
Rafał



2013/9/29 Patrick Burns <pburns@pburns.seanet.com>

> See Circle 8.1.3 of 'The R Inferno'.
>
> http://www.burns-stat.com/**documents/books/the-r-inferno/<http://www.burns-stat.com/documents/books/the-r-inferno/>
>
> Pat
>
>
> On 28/09/2013 16:18, rafael.7@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
>>
>> ______________________________**________________
>> R-help@r-project.org mailing list
>> https://stat.ethz.ch/mailman/**listinfo/r-help<https://stat.ethz.ch/mailman/listinfo/r-help>
>> PLEASE do read the posting guide http://www.R-project.org/**
>> posting-guide.html <http://www.R-project.org/posting-guide.html>
>> and provide commented, minimal, self-contained, reproducible code.
>>
>>
> --
> Patrick Burns
> pburns@pburns.seanet.com
> twitter: @burnsstat @portfolioprobe
> http://www.portfolioprobe.com/**blog <http://www.portfolioprobe.com/blog>
> http://www.burns-stat.com
> (home of:
>  'Impatient R'
>  'The R Inferno'
>  'Tao Te Programming')
>

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