r - Adding a new column to matrix error -

i'm trying add new column existing matrix, getting warning everytime.

i'm trying code:

normdismatrix$newcolumn <- labels 

getting message:

warning message: in normdismatrix$newcolumn <- labels : coercing lhs list

after it, when check matrix, seems null:

dim(normdismatrix) null 

note: labels vectors have numbers between 1 , 4.

what can problem?

as @thelatemail pointed out, $ operator cannot used subset matrix. because matrix single vector dimension attribute. when used $ try add new column, r converted matrix lowest structure $ can used on vector, list.

the function want cbind() (column bind). suppose have matrix m

(m <- matrix(51:70, 4)) #      [,1] [,2] [,3] [,4] [,5] # [1,]   51   55   59   63   67 # [2,]   52   56   60   64   68 # [3,]   53   57   61   65   69 # [4,]   54   58   62   66   70 

to add new column vector called labels, can do

labels <- 1:4 cbind(m, newcolumn = labels) #                     newcolumn # [1,] 51 55 59 63 67         1 # [2,] 52 56 60 64 68         2 # [3,] 53 57 61 65 69         3 # [4,] 54 58 62 66 70         4