[R] levels of an array (strings and numbers)

[Alessandro Antonucci]

Reading a csv file (db.csv) as:

yes,full
no,full
no,empty

I can use the command 'levels' to extract
the different values appearing for each
column as follows:

> d<-read.csv("db.csv")
> levels(d[,2])

which returns

> [1] "empty" "full" 

while, doing the same with a numerical csv file as:

1,6
0,6
0,7

the same instruction returns an empty output instead of 6 7

Any idea about that?

Thanks in advance,
Alessandro

-- 
============================================================
Alessandro Antonucci
Dalle Molle Institute for Artificial Intelligence (IDSIA)
at Idsia			e-mail: alessandro at idsia.ch
Galleria 2			web:   idsia.ch/~alessandro
Via Cantonale			mobile:   +39 339-567-23-28
CH-6928				tel:       +41 58-666-66-70
Manno - Lugano			fax:       +41 58-666-66-61
Switzerland			skype: alessandro.antonucci