R help - Jan 2006 - / Operator not meaningful for factors

Folks,
I have a very basic question. The solution eludes me perhaps because
of my own lack of creativity. I am not attaching a fully reproducible
session because the issue may well be becuase of the way the data file
is, and the data file is large (and I don't know whether I can legally
distribute it). If people can suggest things that might be wrong in my
data or the way that I am reading it, I would be most grateful.

I get the following error message in the session quoted at the end of
this email:
/ not meaningful for factors in: Ops.factor(BookValuePS, Price)

As you can see in that some session, I check that the two vectors
being divided are numeric. I also check that the divisor is not 0 at
any index. I also believe that this is not because of the NA's in the
data. My question is, what are other "problems" that can cause the /
operator to not be meaningful?

I did try some simple examples to try to get the same error. However, 
I am not sure how to put the same NA's that one  gets from
read.table() into a vector:
> a <- c(1, 2, 3, NA);
> a
[1]  1  2  3 NA
> b <- c( 1, 2, 3, 4);
> c <- b / a;
> b
[1] 1 2 3 4
> a <- c(1, 2, 3, );
> c <- b/a;
Warning message:
longer object length
        is not a multiple of shorter object length in: b/a


******** Quoted Session below ********
 > explainPriceSimplified <- read.table("combinedClean.csv",
+                            sep = ",",
header=TRUE);
> attach(explainPriceSimplified);
> summary(explainPriceSimplified);
     Symbol           Date              Price            EPS          
   BookValuePS
 XL     :   98   Min.   :19870630   22     :   61   Min.   :-1.401e+05
  Min.   :-6.901e+05
 ZION   :   97   1st Qu.:19910930   26.5   :   61   1st Qu.: 4.650e-01
  1st Qu.: 3.892e+00
 YRCW   :   72   Median :19960331   27.5   :   58   Median : 1.060e+00
  Median : 7.882e+00
 AA     :   71   Mean   :19957688   30     :   58   Mean   :-1.534e+01
  Mean   : 1.515e+02
 ABS    :   71   3rd Qu.:20001231   25     :   56   3rd Qu.: 1.890e+00
  3rd Qu.: 1.444e+01
 ABT    :   71   Max.   :20041231   (Other):29561   Max.   : 5.309e+03
  Max.   : 3.366e+06
 (Other):29624                      NA's   :  249   NA's   : 2.460e+02
  NA's   : 4.760e+02
 FiscalQuarterRep    F12MRet
 2004/2F:  482    Min.   :-100.00
 2003/4F:  471    1st Qu.:  -8.82
 2004/1F:  470    Median :  10.57
 2004/3F:  470    Mean   :  13.36
 2003/3F:  464    3rd Qu.:  31.12
 2003/2F:  463    Max.   :4700.00
 (Other):27284    NA's   : 463.00
> mode(Price)
[1] "numeric"
> mode(EPS)
[1] "numeric"
> mode(BookValuePS)
[1] "numeric"
> BP <- BookValuePS / Price ;
Warning message:
/ not meaningful for factors in: Ops.factor(BookValuePS,
Price)
> which(Price==0)
numeric(0)
>

--
-- Vivek Satsangi
Student, Rochester, NY USA

But factors are numeric:

mode(factor(1:3)) # numeric

so the numerator or denominator are likely a factor.
Try using str and class rather than mode to investigate
this.


On 1/15/06, Vivek Satsangi <vivek.satsangi at gmail.com>
wrote:
> Folks,
> I have a very basic question. The solution eludes me perhaps because
> of my own lack of creativity. I am not attaching a fully reproducible
> session because the issue may well be becuase of the way the data file
> is, and the data file is large (and I don't know whether I can legally
> distribute it). If people can suggest things that might be wrong in my
> data or the way that I am reading it, I would be most grateful.
>
> I get the following error message in the session quoted at the end of
> this email:
> / not meaningful for factors in: Ops.factor(BookValuePS, Price)
>
> As you can see in that some session, I check that the two vectors
> being divided are numeric. I also check that the divisor is not 0 at
> any index. I also believe that this is not because of the NA's in the
> data. My question is, what are other "problems" that can cause
the /
> operator to not be meaningful?
>
> I did try some simple examples to try to get the same error. However,
> I am not sure how to put the same NA's that one  gets from
> read.table() into a vector:
> > a <- c(1, 2, 3, NA);
> > a
> [1]  1  2  3 NA
> > b <- c( 1, 2, 3, 4);
> > c <- b / a;
> > b
> [1] 1 2 3 4
> > a <- c(1, 2, 3, );
> > c <- b/a;
> Warning message:
> longer object length
>        is not a multiple of shorter object length in: b/a
>
>
> ******** Quoted Session below ********
>  > explainPriceSimplified <-
read.table("combinedClean.csv",
> +                            sep = ",", header=TRUE);
> > attach(explainPriceSimplified);
> > summary(explainPriceSimplified);
>     Symbol           Date              Price            EPS
>   BookValuePS
>  XL     :   98   Min.   :19870630   22     :   61   Min.   :-1.401e+05
>  Min.   :-6.901e+05
>  ZION   :   97   1st Qu.:19910930   26.5   :   61   1st Qu.: 4.650e-01
>  1st Qu.: 3.892e+00
>  YRCW   :   72   Median :19960331   27.5   :   58   Median : 1.060e+00
>  Median : 7.882e+00
>  AA     :   71   Mean   :19957688   30     :   58   Mean   :-1.534e+01
>  Mean   : 1.515e+02
>  ABS    :   71   3rd Qu.:20001231   25     :   56   3rd Qu.: 1.890e+00
>  3rd Qu.: 1.444e+01
>  ABT    :   71   Max.   :20041231   (Other):29561   Max.   : 5.309e+03
>  Max.   : 3.366e+06
>  (Other):29624                      NA's   :  249   NA's   :
2.460e+02
>  NA's   : 4.760e+02
>  FiscalQuarterRep    F12MRet
>  2004/2F:  482    Min.   :-100.00
>  2003/4F:  471    1st Qu.:  -8.82
>  2004/1F:  470    Median :  10.57
>  2004/3F:  470    Mean   :  13.36
>  2003/3F:  464    3rd Qu.:  31.12
>  2003/2F:  463    Max.   :4700.00
>  (Other):27284    NA's   : 463.00
> > mode(Price)
> [1] "numeric"
> > mode(EPS)
> [1] "numeric"
> > mode(BookValuePS)
> [1] "numeric"
> > BP <- BookValuePS / Price ;
> Warning message:
> / not meaningful for factors in: Ops.factor(BookValuePS, Price)
> > which(Price==0)
> numeric(0)
> >
>
>
> --
> -- Vivek Satsangi
> Student, Rochester, NY USA
>
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide!
http://www.R-project.org/posting-guide.html
>

The mode of a factor is numeric, so your test does not do what you think 
it does.

is.numeric() is the recommended test of a vector being numeric.  I have no 
idea where you got the idea that mode() was a useful test (perhaps you 
could give us the reference you used), but it rather rarely is (typeof is 
usually more informative).
>From the summary quoted, Price is clearly a factor.  Test it with 
is.factor.

On Sun, 15 Jan 2006, Vivek Satsangi wrote:
> Folks,
> I have a very basic question. The solution eludes me perhaps because
> of my own lack of creativity. I am not attaching a fully reproducible
> session because the issue may well be becuase of the way the data file
> is, and the data file is large (and I don't know whether I can legally
> distribute it). If people can suggest things that might be wrong in my
> data or the way that I am reading it, I would be most grateful.
>
> I get the following error message in the session quoted at the end of
> this email:
> / not meaningful for factors in: Ops.factor(BookValuePS, Price)
>
> As you can see in that some session, I check that the two vectors
> being divided are numeric.
(see the request above for your reference here)
> I also check that the divisor is not 0 at any index. I also believe that 
> this is not because of the NA's in the data. My question is, what are 
> other "problems" that can cause the / operator to not be
meaningful?
Why not test for factor, since that is what the very helpful error message 
told you the problem was?
> I did try some simple examples to try to get the same error. However,
> I am not sure how to put the same NA's that one  gets from
> read.table() into a vector:
>> a <- c(1, 2, 3, NA);
>> a
> [1]  1  2  3 NA
>> b <- c( 1, 2, 3, 4);
>> c <- b / a;
>> b
> [1] 1 2 3 4
>> a <- c(1, 2, 3, );
>> c <- b/a;
> Warning message:
> longer object length
>        is not a multiple of shorter object length in: b/a
>
>
> ******** Quoted Session below ********
> > explainPriceSimplified <- read.table("combinedClean.csv",
> +                            sep = ",", header=TRUE);
>> attach(explainPriceSimplified);
>> summary(explainPriceSimplified);
>     Symbol           Date              Price            EPS
>   BookValuePS
> XL     :   98   Min.   :19870630   22     :   61   Min.   :-1.401e+05
>  Min.   :-6.901e+05
> ZION   :   97   1st Qu.:19910930   26.5   :   61   1st Qu.: 4.650e-01
>  1st Qu.: 3.892e+00
> YRCW   :   72   Median :19960331   27.5   :   58   Median : 1.060e+00
>  Median : 7.882e+00
> AA     :   71   Mean   :19957688   30     :   58   Mean   :-1.534e+01
>  Mean   : 1.515e+02
> ABS    :   71   3rd Qu.:20001231   25     :   56   3rd Qu.: 1.890e+00
>  3rd Qu.: 1.444e+01
> ABT    :   71   Max.   :20041231   (Other):29561   Max.   : 5.309e+03
>  Max.   : 3.366e+06
> (Other):29624                      NA's   :  249   NA's   :
2.460e+02
>  NA's   : 4.760e+02
> FiscalQuarterRep    F12MRet
> 2004/2F:  482    Min.   :-100.00
> 2003/4F:  471    1st Qu.:  -8.82
> 2004/1F:  470    Median :  10.57
> 2004/3F:  470    Mean   :  13.36
> 2003/3F:  464    3rd Qu.:  31.12
> 2003/2F:  463    Max.   :4700.00
> (Other):27284    NA's   : 463.00
>> mode(Price)
> [1] "numeric"
>> mode(EPS)
> [1] "numeric"
>> mode(BookValuePS)
> [1] "numeric"
>> BP <- BookValuePS / Price ;
> Warning message:
> / not meaningful for factors in: Ops.factor(BookValuePS, Price)
>> which(Price==0)
> numeric(0)
-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

Hi there,

This will sound very stupid because I just started using R but I see you had
similar problems.

I just loaded a very large dataset (2950*6602) from csv into R. The format
is ticker=row, date=column.
Every time I want to compute basic operations, R returns "In Ops.factor:
not
meaningful for factors"

I believe it is because R does not read the data as numbers but I am not
sure. Can anybody help?

Thanks! 
-- 
View this message in context:
http://r.789695.n4.nabble.com/Operator-not-meaningful-for-factors-tp791563p2124697.html
Sent from the R help mailing list archive at Nabble.com.

On May 3, 2010, at 6:22 PM, vincent.deluard wrote:
>
> Hi there,
>
> This will sound very stupid because I just started using R but I see  
> you had
> similar problems.
>
> I just loaded a very large dataset (2950*6602) from csv into R. The  
> format
> is ticker=row, date=column.
Not a particularly precise description of what is in the data.

> Every time I want to compute basic operations, R returns "In  
> Ops.factor: not
> meaningful for factors"
Code .... we want to see code. All of it.
>
> I believe it is because R does not read the data as numbers
Probably true. Were they dates or numbers?
> but I am not
> sure. Can anybody help?
I generally read in my data  with read.table( ,,,,, as.is=TRUE,  
stringsAsFactors=FALSE, ....) and then convert the columns that I know  
should be numeric with as.numeric. If all of your columns should have  
been numeric, you might use the colClasses argument, perhaps along  
these lines:

rd.obj <- read.csv(file="something", colClasses=
rep("numeric",
<number-of-columns>) )

-- 
David Winsemius, MD
West Hartford, CT

Hi David,

 

Thanks for the prompt answer. 

In this file, I have cut the data to the first 15 columns.

Here is the code:

 

t2 <- read.csv(''Test2.csv'', sep=",", header=TRUE)
> Test2[2,2]
[1] 18.72

1994 Levels: 0.24 0.33 0.49 0.53 0.65 0.67 0.72 0.76 0.88 0.9 0.94 ... 98.88
> Test2[2,2]+1
[1] NA

Warning message:

In Ops.factor(Test2[2, 2], 1) : + not meaningful for factors

 

The funny thing is that the same commands work normally for a shorter matrix –
just the 1st 6 rows and columns.

Which led me to think it had to do with the blank cells.

But typing :

Test2 <- read.csv(''Test2.csv'', sep=",",
header=TRUE, na.strings=" ")

does not help.

 

Your help is infinitely appreciated.

 

--------------------------------------------

Vincent Deluard

 <mailto:Vincent.Deluard@TrimTabs.com> Vincent.Deluard@TrimTabs.com

Global Equity Strategist, CFA Charter Award Pending

TrimTabs Investment Research

40 Wall Street, 28th Floor

New York, NY 10005

Phone: (+1) 646-512-5616



From: David Winsemius [via R]
[mailto:ml-node+2124710-750256529-90534@n4.nabble.com]
Sent: Monday, May 03, 2010 6:35 PM
To: vincent.deluard
Subject: Re: / Operator not meaningful for factors




On May 3, 2010, at 6:22 PM, vincent.deluard wrote: 

> 
> Hi there, 
> 
> This will sound very stupid because I just started using R but I see   
> you had 
> similar problems. 
> 
> I just loaded a very large dataset (2950*6602) from csv into R. The  
> format 
> is ticker=row, date=column. 

Not a particularly precise description of what is in the data. 

> Every time I want to compute basic operations, R returns "In   
> Ops.factor: not 
> meaningful for factors" 
Code .... we want to see code. All of it. 
> 
> I believe it is because R does not read the data as numbers 
Probably true. Were they dates or numbers? 
> but I am not 
> sure. Can anybody help? 
I generally read in my data  with read.table( ,,,,, as.is=TRUE,   
stringsAsFactors=FALSE, ....) and then convert the columns that I know   
should be numeric with as.numeric. If all of your columns should have  
been numeric, you might use the colClasses argument, perhaps along   
these lines: 

rd.obj <- read.csv(file="something", colClasses=
rep("numeric",
<number-of-columns>) ) 

-- 
David Winsemius, MD 
West Hartford, CT 

______________________________________________ 
[hidden email] 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. 



  _____  

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AwNTU4Mzk3>  here. 





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	[[alternative HTML version deleted]]

Check you input data.  You have some non-numeric characters in columns where
you are expecting numerics.

The parameter is

stringsAsFactors=FALSE

You had it spelt wrong.  After reading in your data, do the conversion to
numeric and then examine which locations contain NA; this will point you to
the problem line in your input.  Also if you use 'colClasses', I think
it
will error the offending line.

On Mon, May 3, 2010 at 7:21 PM, vincent.deluard <
vincent.deluard@trimtabs.com> wrote:
>
> Hi John,
>
>
>
> Thanks for responding so quickly.
>
>
>
> So I tried:
>
>
>
> Test2[1:3,1:3])
>
> 'data.frame':   3 obs. of  3 variables:
>
>  $ Date      : Factor w/ 2480 levels "A UN Equity",..: 1033 2396
613
>
>  $ X4.20.2010: Factor w/ 1994 levels "0.24","0.33",..:
953 497 1814
>
>  $ X4.19.2010: Factor w/ 1957 levels "0.24","0.33",..:
933 486 1779
>
>
>
> But I am not sure how to interpret it.
>
>
>
> The stringAsFactors = False option did not work either.
>
>
>
> > Test2 <- read.table('Test2.csv', sep=",",
header=TRUE,
> stringAsFactors=FALSE)
>
> Error in read.table("Test2.csv", sep = ",", header =
TRUE, stringAsFactors
> = FALSE) :
>
>  unused argument(s) (stringAsFactors = FALSE)
>
>
>
> If you want to look at it, I attach a section of my data.
>
>
>
> Right now if I type:
>
> > Test2[2,2]+1
>
> Which should return 19.72
>
>
>
> I get
>
> [1] NA
>
> Warning message:
>
> In Ops.factor(Test2[2, 2], 1) : + not meaningful for factors
>
>
>
> Your help is SO appreciated!
>
>
>
> --------------------------------------------
>
> Vincent Deluard
>
>  <mailto:Vincent.Deluard@TrimTabs.com> Vincent.Deluard@TrimTabs.com
>
> Global Equity Strategist, CFA Charter Award Pending
>
> TrimTabs Investment Research
>
> 40 Wall Street, 28th Floor
>
> New York, NY 10005
>
> Phone: (+1) 646-512-5616
>
>
>
> From: John Kane-2 [via R] [mailto:
>
ml-node+2124731-1168690456-90534@n4.nabble.com<ml-node%2B2124731-1168690456-90534@n4.nabble.com>
> ]
> Sent: Monday, May 03, 2010 6:51 PM
> To: vincent.deluard
> Subject: Re: / Operator not meaningful for factors
>
>
>
>  I think that you are correct.  R has the annoying habit of converting
> character data to factors when you don't want it
> to while it is importing data.  This is because the in the option
> "stringsAsFactors" is set to TRUE for some weird
> historical reasons.
>
> Try the command str(insert name of data) and see what happens.  It should
> show you which columns of data are being
> treated as factors.
>
> You can convert the back to character or to numeric.  See the FAQ Part 7
> "How do I convert factors to numeric? " or you
> can use the String as options command in the read.table to FALSE
>
> Something like this should work, I think, but it's not tested
> read.table("C:/rdata/trees.csv", stringsAsFactors=FALSE)
>
>
>
>
>
> --- On Mon, 5/3/10, vincent.deluard <[hidden email]> wrote:
>
>
> > From: vincent.deluard <[hidden email]>
> > Subject: Re: [R] / Operator not meaningful for factors
> > To: [hidden email]
> > Received: Monday, May 3, 2010, 6:22 PM
> >
> > Hi there,
> >
> > This will sound very stupid because I just started using R
> > but I see you had
> > similar problems.
> >
> > I just loaded a very large dataset (2950*6602) from csv
> > into R. The format
> > is ticker=row, date=column.
> > Every time I want to compute basic operations, R returns
> > "In Ops.factor: not
> > meaningful for factors"
> >
> > I believe it is because R does not read the data as numbers
> > but I am not
> > sure. Can anybody help?
> >
> > Thanks!
> > --
> > View this message in context:
>
http://r.789695.n4.nabble.com/Operator-not-meaningful-for-factors-tp791563p2124697.html
> > Sent from the R help mailing list archive at Nabble.com.
> >
> > ______________________________________________
> > [hidden email]
> > mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-help
> > PLEASE do read the posting guide
>
http://www.R-project.org/posting-guide.html<http://www.r-project.org/posting-guide.html>
> > and provide commented, minimal, self-contained,
> > reproducible code.
> >
>
>
> ______________________________________________
> [hidden email] mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
>
http://www.R-project.org/posting-guide.html<http://www.r-project.org/posting-guide.html>
> and provide commented, minimal, self-contained, reproducible code.
>
>
>
>  _____
>
> View message @
>
http://r.789695.n4.nabble.com/Operator-not-meaningful-for-factors-tp791563p2124731.html
> To unsubscribe from Re: / Operator not meaningful for factors, click
> < (link removed)
> AwNTU4Mzk3>  here.
>
>
>
>
>
> --
> View this message in context:
>
http://r.789695.n4.nabble.com/Operator-not-meaningful-for-factors-tp791563p2124759.html
> Sent from the R help mailing list archive at Nabble.com.
>
>        [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help@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<http://www.r-project.org/posting-guide.html>
> and provide commented, minimal, self-contained, reproducible code.
>


-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem that you are trying to solve?

	[[alternative HTML version deleted]]

Hi

"Katya Mauff" <Katya.Mauff at uct.ac.za> napsal dne 04.05.2010
09:53:49:
> another way to do it (if you are still having problems) is to use sapply
> (yourdataname,data.class) after you've read it in, which will tell you 
the 
> data class of each of your variables (factor, numeric etc). You can then 
> change your factor variables to numeric by typing yourdataname
> $variablename=as.numeric(yourdataname$variablename).
You can not!!!!! When you do it you will get numeric **representation** of 
factor levels.
> x<-rnorm(5)
> x
[1] -1.1550254 -0.4578429 -0.6089007 -1.7378599 
0.1297853
> x.f<-factor(x)
> x.f
[1] -1.15502538070463  -0.457842907389024 -0.608900689299125 
-1.73785992416606 
[5] 0.129785271221269 
5 Levels: -1.73785992416606 -1.15502538070463 ...
0.129785271221269
> as.numeric(x.f)
[1] 2 4 3 1 5
>
Regards
Petr


> 
> >>> Petr PIKAL <petr.pikal at precheza.cz> 2010/05/04 09:38
AM >>>
> Hi
> 
> r-help-bounces at r-project.org napsal dne 04.05.2010 00:50:00:
> 
> >  I think that you are correct.  R has the annoying habit of converting
> > character data to factors when you don't want it to while it is 
> importing 
> > data.  This is because the in the option "stringsAsFactors"
is set to
> TRUE for
> > some weird historical reasons.
> 
> It is a matter of opinion. I consider it quite useful feature. If I see 
by
> 
> str(some.data) or summary(data0 that numeric columns are factors I know 
> something is wrong with input.
> 
> and when I want to use ggplot, xyplot or just plot my data with 
different 
> colours/sizes/pchs/.... it is quite easy to use as.numeric(my.factor) to 
> get numeric representation of levels.
> 
> Finally you can easily change labels, concatenate levels and so on.
> 
> Just my 2 cents.
> 
> Regards
> Petr
> 
> 
> 
> > 
> > Try the command str(insert name of data) and see what happens.  It 
> should show
> > you which columns of data are being treated as factors.
> > 
> > You can convert the back to character or to numeric.  See the FAQ Part
7 
> "How 
> > do I convert factors to numeric? " or you can use the String as 
options 
> > command in the read.table to FALSE
> > 
> > Something like this should work, I think, but it's not tested
> > read.table("C:/rdata/trees.csv", stringsAsFactors=FALSE)
> > 
> > 
> > 
> > 
> > 
> > --- On Mon, 5/3/10, vincent.deluard <vincent.deluard at
trimtabs.com>
> wrote:
> > 
> > > From: vincent.deluard <vincent.deluard at trimtabs.com>
> > > Subject: Re: [R] / Operator not meaningful for factors
> > > To: r-help at r-project.org
> > > Received: Monday, May 3, 2010, 6:22 PM
> > > 
> > > Hi there,
> > > 
> > > This will sound very stupid because I just started using R
> > > but I see you had
> > > similar problems.
> > > 
> > > I just loaded a very large dataset (2950*6602) from csv
> > > into R. The format
> > > is ticker=row, date=column.
> > > Every time I want to compute basic operations, R returns
> > > "In Ops.factor: not
> > > meaningful for factors"
> > > 
> > > I believe it is because R does not read the data as numbers
> > > but I am not
> > > sure. Can anybody help?
> > > 
> > > Thanks! 
> > > -- 
> > > View this message in context: 
> http://r.789695.n4.nabble.com/Operator-not-
> > meaningful-for-factors-tp791563p2124697.html
> > > Sent from the R help mailing list archive at Nabble.com.
> > > 
> > > ______________________________________________
> > > 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.
> > >
> > 
> > ______________________________________________
> > 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.
> 
> ______________________________________________
> 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.
> 
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Hi

Yes, it is also possible. I usually use

as.numeric(as.character(some.factor.which can.be.transformed.to.numeric))

Regards
Petr

"Katya Mauff" <Katya.Mauff at uct.ac.za> napsal dne 04.05.2010
10:42:20:
> apologies-try something like this:
> > x<-rnorm(5)
> > x
> [1]  0.9128818  1.5615704 -1.2319878 -1.8689400 -1.2931785
> > x.f<-factor(x)
> > x.f
> [1] 0.912881849717846 1.56157044807315  -1.2319877852522 
-1.8689399737313 
> -1.29317849983031
> Levels: -1.8689399737313 -1.29317849983031 -1.2319877852522 
0.912881849717846 
> 1.56157044807315
> > y=as.numeric(levels(x.f))[x.f]
> > y
> [1]  0.9128818  1.5615704 -1.2319878 -1.8689400 -1.2931785
> 
> 
> 
> 
> 
> >>> Petr PIKAL <petr.pikal at precheza.cz> 2010/05/04 10:12
AM >>>
> 
> > x<-rnorm(5)
> > x
> [1] -1.1550254 -0.4578429 -0.6089007 -1.7378599  0.1297853
> > x.f<-factor(x)
> > x.f
> [1] -1.15502538070463  -0.457842907389024 -0.608900689299125 
> -1.73785992416606 
> [5] 0.129785271221269 
> 5 Levels: -1.73785992416606 -1.15502538070463 ... 0.129785271221269
> > as.numeric(x.f)
> [1] 2 4 3 1 5
> 
> 
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