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???
Antje
Dataframe manipulation
5 messages · Antje, John Kane, David Winsemius +1 more
try this (also look at R-FAQ 7.10): sapply(df, function (x) as.numeric(levels(x))[as.integer(x)]) I hope it helps. Best, Dimitris ---- Dimitris Rizopoulos Ph.D. Student Biostatistical Centre School of Public Health Catholic University of Leuven Address: Kapucijnenvoer 35, Leuven, Belgium Tel: +32/(0)16/336899 Fax: +32/(0)16/337015 Web: http://med.kuleuven.be/biostat/ http://www.student.kuleuven.be/~m0390867/dimitris.htm ----- Original Message ----- From: "Antje" <niederlein-rstat at yahoo.de> To: <r-help at stat.math.ethz.ch> 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???
Antje
______________________________________________ R-help at r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm
See R-FAQ # 7-11 for the solution. Have a look at http://finzi.psych.upenn.edu/R/Rhelp02a/archive/98227.html for a discussion of this type of problem and ways to get around the issue.
--- Antje <niederlein-rstat at yahoo.de> wrote:
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???
Antje
______________________________________________ R-help at r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
"Dimitris Rizopoulos" <dimitris.rizopoulos at med.kuleuven.be> wrote in news:002001c8367f$65a8d8d0$0540210a at www.domain:
try this (also look at R-FAQ 7.10): sapply(df, function (x) as.numeric(levels(x))[as.integer(x)])
That looks rather dangerous. By the time I saw your suggestion, I had already added an extra variable with: df$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" <niederlein-rstat at yahoo.de>
> To: <r-help at stat.math.ethz.ch>
> 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???
>>
my original reply was intended for the original version of 'df', in
which both columns were factors. In your example you have added a
numeric column, so not exactly the case I've replied for. For your
example can use the following:
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)
df$testdata1 <-
as.numeric(levels(df$testdata))[as.integer(df$testdata)]
fcts <- sapply(df, is.factor)
df[fcts] <- lapply(df[fcts], function (x)
as.numeric(levels(x))[as.integer(x)])
df
str(df)
Best,
Dimitris
----
Dimitris Rizopoulos
Ph.D. Student
Biostatistical Centre
School of Public Health
Catholic University of Leuven
Address: Kapucijnenvoer 35, Leuven, Belgium
Tel: +32/(0)16/336899
Fax: +32/(0)16/337015
Web: http://med.kuleuven.be/biostat/
http://www.student.kuleuven.be/~m0390867/dimitris.htm
----- Original Message -----
From: "David Winsemius" <dwinsemius at comcast.net>
To: <r-help at stat.math.ethz.ch>
Sent: Tuesday, December 04, 2007 4:47 PM
Subject: Re: [R] Dataframe manipulation
"Dimitris Rizopoulos" <dimitris.rizopoulos at med.kuleuven.be> wrote in news:002001c8367f$65a8d8d0$0540210a at www.domain:
try this (also look at R-FAQ 7.10): sapply(df, function (x) as.numeric(levels(x))[as.integer(x)])
That looks rather dangerous. By the time I saw your suggestion, I had already added an extra variable with: df$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" <niederlein-rstat at yahoo.de> To: <r-help at stat.math.ethz.ch> 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???
______________________________________________ R-help at r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm