R: Converting a data frame into a matrix

Question

I have a matrix written to a csv file.

I'm trying to read the file and get the data as a matrix. I have used as.matrix and data.matrix functions. However I'm unable to load the data as a matrix. My goal is to use this distance matrix for hierarchical clustering.

Answer 1

We can use read.csv to read the .csv file, set the first column as row names (row.names=1), and converting to matrix (as.matrix) should work fine.

  d1 <- read.csv('Test_Matrix.csv', row.names=1)
  m1 <- as.matrix(d1)
  m1
  #  A B C D
  #A 0 1 2 3
  #B 1 0 4 5
  #C 2 4 0 6
  #D 3 5 6 0
  is.matrix(m1)
  #[1] TRUE

Or as @RHertel mentioned in the comments, we can combine both in a single step

  as.matrix(read.csv('Test_Matrix.csv', row.names=1))