CODEWITHSUNDEEP
rmatrixvector
Hannah Harder
Hannah Harder

Reputation: 67

Subtract vector from one column of a matrix

I'm a complete R novice, and I'm really struggling on this problem. I need to take a vector, evens, and subtract it from the first column of a matrix, top_secret. I tried to call up only that column using top_secret[,1] and subtract the vector from that, but then it only returns the column. Is there a way to do this inside the matrix so that I can continue to manipulate the matrix without creating a bunch of separate columns?

Upvotes: 0

Views: 437

Answers (2)

akrun
akrun

Reputation: 887971

Or another option is replace

replace(m, cbind(seq_len(nrow(m)), 4), m[,4] - 5)

data

m <- matrix(c(1,2,3,4),4,4, byrow = TRUE)

Upvotes: 0

slava-kohut
slava-kohut

Reputation: 4233

Sure, you can. Here is an example:

m <- matrix(c(1,2,3,4),4,4, byrow = TRUE)

> m
     [,1] [,2] [,3] [,4]
[1,]    1    2    3    4
[2,]    1    2    3    4
[3,]    1    2    3    4
[4,]    1    2    3    4

m[,4] <- m[,4] - c(5,5,5,5)

which gives:

> m
     [,1] [,2] [,3] [,4]
[1,]    1    2    3   -1
[2,]    1    2    3   -1
[3,]    1    2    3   -1
[4,]    1    2    3   -1

Upvotes: 2

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