R help - Aug 2006 - levels of an array (strings and numbers)

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
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Switzerland			skype: alessandro.antonucci

Alessandro Antonucci wrote:
> 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
R (i.e. read.csv) assumes this is numeric rather than categorical data.
Hence specify the class of each variable in read.cvs' argument
"colClasses".

Uwe Ligges


> the same instruction returns an empty output instead of 6 7
> 
> Any idea about that?
> 
> Thanks in advance,
> Alessandro
>