Question

I have a problem that is hampering my analyses. For some weird reason, whenever I import a table (csv, text etc) I never get the row numbers to appear in brackets. Instead of this:

>ID Year  
[1,]  1 1944  
[2,]  1 1945  
[3,]  1 1946  

I get this:

ID Year
1 1 1944
2 1 1945
3 1 1946

The problem is that R ends up using the first column (1,2,3) as ID and ruins the analysis.
Any ideas?

Thank you!

Answer 1

Your “object printed with row numbers in brackets” is probably a matrix, while reading from csv you get a data.frame.

If you call as.matrix() on the data.frame you get by reading the csv, you will obtain the desired result.

e.g. :

A matrix object like this:

m1 <- matrix(c(1,1,1,1944,1945,1946),nrow=3,ncol=2)
colnames(m1) <- c('ID','Year')

m1

yields:

> m1
     ID Year
[1,]  1 1944
[2,]  1 1945
[3,]  1 1946

While reading the same data from a csv:

m2 <- read.csv(text="ID,Year
1,1944
1,1945
1,1946")

m2

you get:

> m2
  ID Year
1  1 1944
2  1 1945
3  1 1946

Converting m2 to a matrix:

m3 <- as.matrix(m2)
m3

you get this:

> m3
     ID Year
[1,]  1 1944
[2,]  1 1945
[3,]  1 1946