Export matrix in r
You don't get a new column, the row names are saved as a first column in the text file. So either you specify the column where the row names are given in
read.table, or use the
row.names=FALSE option in
mat <- matrix(1:10,ncol=2) rownames(mat) <- letters[1:5] colnames(mat) <- LETTERS[1:2] mat write.table(mat,file="test.txt") # keeps the rownames read.table("test.txt",header=TRUE,row.names=1) # says first column are rownames unlink("test.txt") write.table(mat,file="test2.txt",row.names=FALSE) # drops the rownames read.table("test.txt",header=TRUE) unlink("test2.txt")
I assume that by "new column" you mean the row names that get written out by default. To suppress them, set
row.names = FALSE when calling
write.table package:utils R Documentation Data Output Description: ‘write.table’ prints its required argument ‘x’ (after converting it to a data frame if it is not one nor a matrix) to a file or connection. Usage: write.table(x, file = "", append = FALSE, quote = TRUE, sep = " ", eol = "\n", na = "NA", dec = ".", row.names = TRUE, col.names = TRUE, qmethod = c("escape", "double")) write.csv(...) write.csv2(...) ... row.names: either a logical value indicating whether the row names of ‘x’ are to be written along with ‘x’, or a character vector of row names to be written. col.names: either a logical value indicating whether the column names of ‘x’ are to be written along with ‘x’, or a character vector of column names to be written. See the section on ‘CSV files’ for the meaning of ‘col.names = NA’.