"Dimitris Rizopoulos" <[EMAIL PROTECTED]> wrote in
news:[EMAIL PROTECTED]:
> try this (also look at R-FAQ 7.10):
>
> sapply(df, function (x) as.numeric(levels(x))[as.integer(x)])
That looks rather dangerous. By the time I saw your suggestion, I had
already added an extra variable with:
df$testdata1<-as.numeric(levels(df$testdata))[as.integer(df$testdata)]
When I tried your suggestion I got no error, but there was also no
effect. When I tried:
df2<-sapply(df, function (x) as.numeric(levels(x))[as.integer(x)])
I discovered that the numeric variable, testdata1, had been entirely
coverted to NA's and str(df2) did not look data.frame-like.
> is.data.frame(df2)
[1] FALSE
--
David Winsemius
>
> ----- Original Message -----
> From: "Antje" <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>
> Sent: Tuesday, December 04, 2007 11:46 AM
> Subject: [R] Dataframe manipulation
>
>
>> Hello,
>>
>> can anybody help me with this problem?
>> I have a dataframe, which contains its values as factors though I
>> have numbers
>> but it was read as factors with "scan". Now I would like to convert
>> these
>> columns (multiple) to a numeric format.
>>
>>
>> # this example creates a similar situation
>>
>> testdata <- as.factor(c("1.1",NA,"2.3","5.5"))
>> testdata2 <- as.factor(c("1.7","4.3","8.5",10.0))
>>
>> df <- data.frame(testdata, testdata2)
>>
>> what do I have to do to get the same datafram but with numeric
>> values???
>>
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