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Hans-Juergen Eickelmann

2006-Dec-05 15:33 UTC

[R] if(){} else{}

Dear R-community,

my data set looks like 'mat' below.

Plant<-c(NA,1,1,1,NA,NA,NA,NA,NA,1);
Value1<-rnorm(1:10);
Value2<-rnorm(1:10);
mat<-cbind(Plant,Value1,Value2);
I receive data from two different sites.
One site is identified by an interger number, the other site has no data in
column Plant=NA.

My pb:

I'm trying to assign labels "A" or "B" to these 2 sites
into a new column,
but my if(){} else{} statement fails with the following statement:
Error in if (is.na(mat$Plant == TRUE)) { :
        argument is of length zero

if(is.na(mat$Plant==TRUE)){mat$Plant1="A"}
else{mat$Plant1="B"};

I looked through the avail doc and R-help for some time but wasn't able to
fix the pb.

Thx Hans

Greg Snow

2006-Dec-05 16:25 UTC

head link

[R] if(){} else{}

Try this version:

Plant<-c(NA,1,1,1,NA,NA,NA,NA,NA,1);
Value1<-rnorm(10);
Value2<-rnorm(10);
mat<-data.frame(Plant,Value1,Value2);

mat <- transform(mat, Plant1=ifelse(is.na(Plant),
"A","B"))


A couple of comments on your original code:

The 1:10 in the rnorm calls is unnecessary since rnorm just takes the
length of the vector, just tell rnorm how many numbers you want (or you
could do rnorm(Plant) to have R count for you).

The cbind function creates a matrix, the notation mat$Plant assumes that
mat is a list or data frame and that is why you received the error.

The  if (){} else {} syntax is usually for program flow and looks for a
scalar value, the function ifelse is vectorized and usefull for vectors
(which is what it looks like you wanted).

The transform function is nice in that it allows you to skip some of the
indexing.

Hope this helps,

-- 
Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg.snow at intermountainmail.org
(801) 408-8111
 

-----Original Message-----
From: r-help-bounces at stat.math.ethz.ch
[mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Hans-Juergen
Eickelmann
Sent: Tuesday, December 05, 2006 8:33 AM
To: r-help at stat.math.ethz.ch
Subject: [R] if(){} else{}


Dear R-community,

my data set looks like 'mat' below.

Plant<-c(NA,1,1,1,NA,NA,NA,NA,NA,1);
Value1<-rnorm(1:10);
Value2<-rnorm(1:10);
mat<-cbind(Plant,Value1,Value2);
I receive data from two different sites.
One site is identified by an interger number, the other site has no data
in column Plant=NA.

My pb:

I'm trying to assign labels "A" or "B" to these 2 sites
into a new
column, but my if(){} else{} statement fails with the following
statement:
Error in if (is.na(mat$Plant == TRUE)) { :
        argument is of length zero

if(is.na(mat$Plant==TRUE)){mat$Plant1="A"}
else{mat$Plant1="B"};

I looked through the avail doc and R-help for some time but wasn't able
to fix the pb.

Thx Hans

______________________________________________
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
and provide commented, minimal, self-contained, reproducible code.

David Scott

2006-Dec-05 16:26 UTC

head link

[R] if(){} else{}

Test should be

if(is.na(mat$Plant)){ ...



On Tue, 5 Dec 2006, Hans-Juergen Eickelmann wrote:
>
> Dear R-community,
>
> my data set looks like 'mat' below.
>
> Plant<-c(NA,1,1,1,NA,NA,NA,NA,NA,1);
> Value1<-rnorm(1:10);
> Value2<-rnorm(1:10);
> mat<-cbind(Plant,Value1,Value2);
> I receive data from two different sites.
> One site is identified by an interger number, the other site has no data in
> column Plant=NA.
>
> My pb:
>
> I'm trying to assign labels "A" or "B" to these 2
sites into a new column,
> but my if(){} else{} statement fails with the following statement:
> Error in if (is.na(mat$Plant == TRUE)) { :
>        argument is of length zero
>
> if(is.na(mat$Plant==TRUE)){mat$Plant1="A"}
else{mat$Plant1="B"};
>
> I looked through the avail doc and R-help for some time but wasn't able
to
> fix the pb.
>
> Thx Hans
>
> ______________________________________________
> 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
> and provide commented, minimal, self-contained, reproducible code.
>
_________________________________________________________________
David Scott	Visiting (Until January 07)
 		Department of Probability and Statistics
 		The University of Sheffield
 		The Hicks Building
 		Hounsfield Road
 		Sheffield S3 7RH
 		United Kingdom
Phone:	+44 114 222 3908
Email:	d.scott at auckland.ac.nz

Gavin Simpson

2006-Dec-05 16:46 UTC

head link

[R] if(){} else{}

On Tue, 2006-12-05 at 16:33 +0100, Hans-Juergen Eickelmann
wrote:> Dear R-community,
> 
> my data set looks like 'mat' below.
> 
> Plant<-c(NA,1,1,1,NA,NA,NA,NA,NA,1);
> Value1<-rnorm(1:10);
You only really need rnorm(10), as in ?rnorm, rnorm is defined as
rnorm(n, mean=0, sd=1) and n is the number of observations.
> Value2<-rnorm(1:10);
> mat<-cbind(Plant,Value1,Value2);
You don't need the ";" at the ends of the lines, and cbind()
returns a
matrix, for which you cannot use "$" to access the columns:
> class(mat)
[1] "matrix"> mat$PlantNULL

What you are looking for is ifelse(), see ?ifelse, but here is your
example, suitable spaced out and minus the other infelicities.

Plant <- c(NA, 1, 1, 1, NA, NA, NA, NA, NA, 1)
Value1 <- rnorm(10)
Value2 <- rnorm(10)
mat <- data.frame(Plant, Value1, Value2)
mat$Plant1 <- ifelse(is.na(mat$Plant), "A", "B")
> mat$Plant1 [1] "A" "B" "B" "B" "A"
"A" "A" "A" "A"
"B"> mat   Plant      Value1      Value2 Plant1
1     NA  2.76603270 -0.20435729      A
2      1 -0.54688170 -0.81943566      B
3      1  0.30480812 -0.05404563      B
4      1  1.64959026 -0.10762260      B
5     NA  1.13528236 -0.04670294      A
6     NA  1.55636761  0.87617575      A
7     NA  0.40651924  1.90516887      A
8     NA  1.49827147  0.05080935      A
9     NA -0.04396752  0.53267040      A
10     1  0.42714137 -0.55944595      B

HTH

G
> I receive data from two different sites.
> One site is identified by an interger number, the other site has no data in
> column Plant=NA.
> 
> My pb:
> 
> I'm trying to assign labels "A" or "B" to these 2
sites into a new column,
> but my if(){} else{} statement fails with the following statement:
> Error in if (is.na(mat$Plant == TRUE)) { :
>         argument is of length zero
> 
> if(is.na(mat$Plant==TRUE)){mat$Plant1="A"}
else{mat$Plant1="B"};
That's not how you use is.na(), see ?is.na, as is.na(x) returns
TRUE/FLASE depending on wither x is NA or not
> I looked through the avail doc and R-help for some time but wasn't able
to
> fix the pb.
> 
> Thx Hans
> 
> ______________________________________________
> 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
> and provide commented, minimal, self-contained, reproducible code.-- 
%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%
 Gavin Simpson                 [t] +44 (0)20 7679 0522
 ECRC & ENSIS, UCL Geography,  [f] +44 (0)20 7679 0565
 Pearson Building,             [e] gavin.simpsonATNOSPAMucl.ac.uk
 Gower Street, London          [w] http://www.ucl.ac.uk/~ucfagls/
 UK. WC1E 6BT.                 [w] http://www.freshwaters.org.uk
%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%

Andrew Robinson

2006-Dec-05 19:39 UTC

head link

[R] if(){} else{}

Hi Hans,

try this ...

mat <- as.data.frame(cbind(Plant,Value1,Value2))

mat$Plant1 <- ifelse(is.na(mat$Plant), "A", "B")

Cheers

Andrew


On Tue, Dec 05, 2006 at 04:33:15PM +0100, Hans-Juergen Eickelmann
wrote:> 
> Dear R-community,
> 
> my data set looks like 'mat' below.
> 
> Plant<-c(NA,1,1,1,NA,NA,NA,NA,NA,1);
> Value1<-rnorm(1:10);
> Value2<-rnorm(1:10);
> mat<-cbind(Plant,Value1,Value2);
> I receive data from two different sites.
> One site is identified by an interger number, the other site has no data in
> column Plant=NA.
> 
> My pb:
> 
> I'm trying to assign labels "A" or "B" to these 2
sites into a new column,
> but my if(){} else{} statement fails with the following statement:
> Error in if (is.na(mat$Plant == TRUE)) { :
>         argument is of length zero
> 
> if(is.na(mat$Plant==TRUE)){mat$Plant1="A"}
else{mat$Plant1="B"};
> 
> I looked through the avail doc and R-help for some time but wasn't able
to
> fix the pb.
> 
> Thx Hans
> 
> ______________________________________________
> 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
> and provide commented, minimal, self-contained, reproducible code.
-- 
Andrew Robinson  
Department of Mathematics and Statistics            Tel: +61-3-8344-9763
University of Melbourne, VIC 3010 Australia         Fax: +61-3-8344-4599
http://www.ms.unimelb.edu.au/~andrewpr
http://blogs.mbs.edu/fishing-in-the-bay/

Petr Pikal

2006-Dec-06 08:49 UTC

head link

[R] if(){} else{}

Hi

a little bit quicker solution is based on subsetting and a fact that 
logical vector can be treated as numeric with FALSE=0 and TRUE = 1

Plant<-sample(c(NA,1), 100000, replace=T);
Value1<-rnorm(Plant);
Value2<-rnorm(Plant);
mat<-data.frame(Plant=Plant,Value1=Value1,Value2=Value2)
>
system.time(mat$Plant1<-c("B","A")[is.na(mat$Plant)+1])
[1] 0.03 0.02 0.05   NA   NA> system.time(mat$Plant2 <- ifelse(is.na(mat$Plant), "A",
"B"))
[1] 0.28 0.01 0.30   NA   NA> with(mat, all.equal(Plant1, Plant2))[1] TRUE

HTH
Petr



On 6 Dec 2006 at 6:39, Andrew Robinson wrote:

Date sent:      	Wed, 6 Dec 2006 06:39:32 +1100
From:           	Andrew Robinson <A.Robinson at ms.unimelb.edu.au>
To:             	Hans-Juergen Eickelmann <EICKELMA at de.ibm.com>
Copies to:      	r-help at stat.math.ethz.ch
Subject:        	Re: [R] if(){} else{}
> Hi Hans,
> 
> try this ...
> 
> mat <- as.data.frame(cbind(Plant,Value1,Value2))
> 
> mat$Plant1 <- ifelse(is.na(mat$Plant), "A", "B")
> 
> Cheers
> 
> Andrew
> 
> 
> On Tue, Dec 05, 2006 at 04:33:15PM +0100, Hans-Juergen Eickelmann
> wrote: > > Dear R-community, > > my data set looks like
'mat' below. >
> > Plant<-c(NA,1,1,1,NA,NA,NA,NA,NA,1); > Value1<-rnorm(1:10);
>
> Value2<-rnorm(1:10); > mat<-cbind(Plant,Value1,Value2); > I
receive
> data from two different sites. > One site is identified by an interger
> number, the other site has no data in > column Plant=NA. > > My
pb: >
> > I'm trying to assign labels "A" or "B" to
these 2 sites into a new
> column, > but my if(){} else{} statement fails with the following
> statement: > Error in if (is.na(mat$Plant == TRUE)) { : >        
> argument is of length zero > >
> if(is.na(mat$Plant==TRUE)){mat$Plant1="A"}
else{mat$Plant1="B"}; > > I
> looked through the avail doc and R-help for some time but wasn't able
> to > fix the pb. > > Thx Hans > >
> ______________________________________________ >
> 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 > and
> provide commented, minimal, self-contained, reproducible code.
> 
> -- 
> Andrew Robinson  
> Department of Mathematics and Statistics            Tel:
> +61-3-8344-9763 University of Melbourne, VIC 3010 Australia        
> Fax: +61-3-8344-4599 http://www.ms.unimelb.edu.au/~andrewpr
> http://blogs.mbs.edu/fishing-in-the-bay/
> 
> ______________________________________________
> 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 and provide commented,
> minimal, self-contained, reproducible code.
Petr Pikal
petr.pikal at precheza.cz

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