[R] Switch two rows in a matrix

[Birgitle]

sorry here the right thing

a<-a[c(1,3,2,4),c(1,3,2,4)]

B.


Birgitle wrote:
> 
> You could perhaps do it like that
> 
> a<-a[c(1,2,4,3),]
> 
> B.
> 
> 
> Zhang Yanwei - Princeton-MRAm wrote:
>> 
>> Hi all,
>>   I have a 4 by 4 matrix, and I want to switch row 2 and row 3 first,
>> then switch column 2 and column 3. Is there an easy way to do it?
>> The following is a tedious way to get what I want. But I wonder if there
>> is a way to simplify this.
>> 
>>  > a=matrix(rnorm(16),4,4)
>>> a
>>             [,1]       [,2]        [,3]       [,4]
>> [1,]  0.33833811 -0.9422273 -0.06181611 -1.8346134
>> [2,] -0.68167996  0.2004836  0.71079887 -1.1590184
>> [3,]  0.07811688  0.1338694 -1.61262688  0.2988365
>> [4,]  0.21869786 -1.6356661 -0.13694344 -1.2121355
>>> b=a
>>> b[2,]=a[3,]
>>> b[3,]=a[2,]
>>> b
>>             [,1]       [,2]        [,3]       [,4]
>> [1,]  0.33833811 -0.9422273 -0.06181611 -1.8346134
>> [2,]  0.07811688  0.1338694 -1.61262688  0.2988365
>> [3,] -0.68167996  0.2004836  0.71079887 -1.1590184
>> [4,]  0.21869786 -1.6356661 -0.13694344 -1.2121355
>>> c=b
>>> c[,2]=b[,3]
>>> c[,3]=b[,2]
>>> c
>>             [,1]        [,2]       [,3]       [,4]
>> [1,]  0.33833811 -0.06181611 -0.9422273 -1.8346134
>> [2,]  0.07811688 -1.61262688  0.1338694  0.2988365
>> [3,] -0.68167996  0.71079887  0.2004836 -1.1590184
>> [4,]  0.21869786 -0.13694344 -1.6356661 -1.2121355
>> 
>> 
>> Sincerely,
>> Yanwei Zhang
>> Department of Actuarial Research and Modeling
>> Munich Re America
>> Tel: 609-275-2176
>> Email: yzhang at munichreamerica.com<mailto:yzhang at munichreamerica.com>
>> 
>> 
>> 	[[alternative HTML version deleted]]
>> 
>> ______________________________________________
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>> 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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