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rmathmatrixoperation

R: Subtract A[i,] from each row B[i,]

How can I perform a simple matrix operation in R to find matrix C?

A = (a11 a12 a13)   B = (b1)   C = (a11-b1 a12-b1 a13-b1)
    (a21 a22 a23)       (b2)       (a21-b2 a22-b2 a23-b2)
    (a31 a32 a33)       (b3)       (a31-b3 a32-b3 a33-b3)

Thanks for your time! Much appreciated! :)

Solution

  • Following is the solution:

    a=matrix(c(1:9), nrow = 3, ncol = 3)
b=matrix(c(1:3),nrow = 3,ncol = 1)
ans=c()
for(i in 1:ncol(a)){
ans=c(ans,a[,i]-b[,1])
}
final=matrix(ans,nrow = 3,ncol = 3)

    The above code produce the following output:

    > a
      [,1] [,2] [,3]
[1,]    1    4    7
[2,]    2    5    8
[3,]    3    6    9
> b
      [,1]
[1,]    1
[2,]    2
[3,]    3
> final
      [,1] [,2] [,3]
[1,]    0    3    6
[2,]    0    3    6
[3,]    0    3    6

    Hope this works for you :)