[R] mirror vector?

[Uwe Ligges]

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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> Jacques VESLOT
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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
>>
>>  		
>> ---------------------------------
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> 
> ______________________________________________
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> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.