[R] Problem using read.xls - Everything converted to factors
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",
)
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
Hm. That shall work. You have got some advice from Gabor but in case
numeric columns come as non numeric I often find a problem with some kind
of formating the original values. Numbers like 10 253,52 are treated as
nonnumeric as there is extra space character between thousands and
hundereds. Maybe also na.strings are not always marked as n.a. but
sometimes the value is missing and I suppose this can lead to conversion
of all column to character vector.
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
you can spare some time to use sapply
testfile[,character columns] <- sapply(testfile[,character columns],
as.numeric)
shall convert all character columns to numeric at once but you will get
NAs to all values which could not be converted for any reason.
Regards
Petr
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