[R] mirror vector?

Uwe Ligges ligges at statistik.uni-dortmund.de
Fri Jul 28 10:25:16 CEST 2006


Jacques VESLOT wrote:
>  > mat <- matrix(1:16,4,4)
>  > mat
>       [,1] [,2] [,3] [,4]
> [1,]    1    5    9   13
> [2,]    2    6   10   14
> [3,]    3    7   11   15
> [4,]    4    8   12   16
>  > apply(mat,2,rev)
>       [,1] [,2] [,3] [,4]
> [1,]    4    8   12   16
> [2,]    3    7   11   15
> [3,]    2    6   10   14
> [4,]    1    5    9   13


or a lot faster:

mat[nrow(mat):1, ]

Uwe Ligges




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> niederlein-rstat at yahoo.de a écrit :
>> Hello,
>>
>> I'm an absolut beginner with R and now I got a 2D vector with numbers. I would like to mirror this vector now by the rows (so that the first row becomes last, second becomes one before last, ...).
>> I don't know if there is any method I can use to do this.
>> Could you please help me?
>>
>> Antje
>>
>>  		
>> ---------------------------------
>> Was Sie schon immer wissen wollten aber nie zu Fragen trauten? Yahoo! Clever hilft Ihnen.
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