[R] Problem using read.xls - Everything converted to factors

[Sebastian Lerch]

Hallo,

I would like to use to read.xls function from the gdata package to read 
data from Microsoft Excel files but I experienced a problem: For example 
I used the following code:

testfile<-read.xls("/home/.../wsjecon0603.xls", #file path
            header=F,
            dec=",",
            na.strings="n.a.",
            skip=5,
            sheet=2,
            col.names=c("Name", "Firm","GDP1","GDP2","GDP3","GDP4","CPI5",
             
"CPI11","UNEMP5","UNEMP11","PROF03","PROF04","STARTS03","STARTS04"),
            nrows=54,
            
#colClasses=c(character,character,numeric,numeric,numeric,numeric,numeric,numeric,numeric,numeric,numeric,numeric,numeric,numeric)

)
print(testfile)

Although the xls file contains numeric values in all the columns except 
the ones which I named "Name" and "Firm", everything in the data frame 
has "factor" as class. I tried to use the colClasses option as above and 
as well with " "'s around each word, but this does not work and I will 
always receive the following error:

Fehler in is(object, Class) :
   versuche einen Slot "className" von einem Objekt der einfachen Klasse 
("list") ohne Slots anzufordern
Calls: read.xls -> read.csv -> read.table -> <Anonymous> -> is

After some hours of reasearch I figured out how I can manually change 
the classes of the columns:

testfile$GDP2<-as.numeric(levels(testfile$GDP2))[testfile$GDP2]
testfile$Name<-as.character(levels(testfile$Name))[testfile$Name] #and so on

This works, but is a lot of work since I have to import many different 
data sets. So I was wondering if there is another way to let the classes 
be recognized correctly.

Additionally I would like to know if there is any way to import data 
from different sheets with the same layout at once into one data frame.

I use Ubuntu 11.04 with Rkward if this is of any importance.

Thanks in advance for your answers,
Sebastian