[R] How to refer to the last a few rows?

jim holtman jholtman at gmail.com
Thu Nov 5 16:32:21 CET 2009


With the flexibility of R, you can always create a function that will
allow you to avoid retyping.

On Thu, Nov 5, 2009 at 9:17 AM, Peng Yu <pengyu.ut at gmail.com> wrote:
> On Thu, Nov 5, 2009 at 7:24 AM, jim holtman <jholtman at gmail.com> wrote:
>> will this do:
>>
>>> x
>>     [,1] [,2] [,3] [,4] [,5]
>> [1,]    1    6   11   16   21
>> [2,]    2    7   12   17   22
>> [3,]    3    8   13   18   23
>> [4,]    4    9   14   19   24
>> [5,]    5   10   15   20   25
>>> tail(x[,tail(seq(ncol(x),3))], 2)
>>     [,1] [,2] [,3]
>> [4,]   24   19   14
>> [5,]   25   20   15
>>>
>
> I would avoid to type the variable name twice. Because this is very
> inconvenient when the variable name is long.
>
> a_loooooooooooooooooong_expression_or_variable[nrow(a_loooooooooooooooooong_expression_or_variable),]
>
> BTW, you misunderstood my question. My question was whether is a
> better way to get the last a few columns than 't(tail(t(x),2))'.
>
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>



-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem that you are trying to solve?




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