R help - Feb 2008 - Concatenate a Variable

Good morning!

I do not speak English very well and so I will try to explain the best I 
can. I have this:

 > tabela[,1]
[1] a a b b a c b a c c c c c
Levels: a b c

 >unique(tabela[,1])
[1] a b c
Levels: a b c

 >var<-unique(tabela[,1])[1]

 > var
[1] a
Levels: a b c

But if I concatenate like this
 > cat("VAR: ", var, "\n")

I obtain
 >VAR:  1

and I want to obtain
 >VAR: a

How can I do this? Thanks!

Hi Carla,

Try paste("VAR: ",a,sep="")


Jorge


On 2/1/08, Carla Rebelo <crebelo@liaad.up.pt>
wrote:
>
> Good morning!
>
> I do not speak English very well and so I will try to explain the best I
> can. I have this:
>
> > tabela[,1]
> [1] a a b b a c b a c c c c c
> Levels: a b c
>
> >unique(tabela[,1])
> [1] a b c
> Levels: a b c
>
> >var<-unique(tabela[,1])[1]
>
> > var
> [1] a
> Levels: a b c
>
> But if I concatenate like this
> > cat("VAR: ", var, "\n")
>
> I obtain
> >VAR:  1
>
> and I want to obtain
> >VAR: a
>
> How can I do this? Thanks!
>
> ______________________________________________
> 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
> and provide commented, minimal, self-contained, reproducible code.
	[[alternative HTML version deleted]]

Carla Rebelo wrote:
> Good morning!
> 
> I do not speak English very well and so I will try to explain the best I 
> can. I have this:
> 
>  > tabela[,1]
> [1] a a b b a c b a c c c c c
> Levels: a b c
> 
>  >unique(tabela[,1])
> [1] a b c
> Levels: a b c
> 
>  >var<-unique(tabela[,1])[1]
> 
>  > var
> [1] a
> Levels: a b c
> 
> But if I concatenate like this
>  > cat("VAR: ", var, "\n")
> 
> I obtain
>  >VAR:  1
> 
> and I want to obtain
>  >VAR: a
> 
> How can I do this? Thanks!
'a' is a factor, thus you are getting the underlying numeric code as the
output.

Note from ?cat:

Currently only atomic vectors (and so not lists) and names are handled.
Character strings are output ?as is? (unlike print.default which escapes
non-printable characters and backslash ? use encodeString if you want to
output encoded strings using cat). Other types of R object should be
converted (e.g. by as.character or format) before being passed to cat.


Thus:

var <- factor("a", levels = c("a", "b",
"c"))
> var
[1] a
Levels: a b c
> is.vector(var)
[1] FALSE


So 'var' is not an atomic vector and you must therefore coerce it to a
character vector using as.character() before passing it to cat():
> cat("VAR: ", as.character(var), "\n")
VAR:  a


HTH,

Marc Schwartz

Carla Rebelo wrote:
> Good morning!
>
> I do not speak English very well and so I will try to explain the best I 
> can. I have this:
>
>  > tabela[,1]
> [1] a a b b a c b a c c c c c
> Levels: a b c
>
>  >unique(tabela[,1])
> [1] a b c
> Levels: a b c
>
>  >var<-unique(tabela[,1])[1]
>
>  > var
> [1] a
> Levels: a b c
>
> But if I concatenate like this
>  > cat("VAR: ", var, "\n")
>
> I obtain
>  >VAR:  1
>
> and I want to obtain
>  >VAR: a
>
> How can I do this? Thanks!
>
>   
The devil is in the Details .... -section of help(cat):

     >>>Other types of R object should be converted
     (e.g. by 'as.character' or 'format') before being passed to
'cat'. <<<
> cat("VAR: ", factor("a"), "\n")
VAR:  1
> cat("VAR: ", format(factor("a")), "\n")
VAR:  a
> cat("VAR: ", as.character(factor("a")), "\n")
VAR:  a

> ______________________________________________
> 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.
>   

-- 
   O__  ---- Peter Dalgaard             ?ster Farimagsgade 5, Entr.B
  c/ /'_ --- Dept. of Biostatistics     PO Box 2099, 1014 Cph. K
 (*) \(*) -- University of Copenhagen   Denmark          Ph:  (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)                  FAX: (+45) 35327907

R is treating tablea[,1] as a factor.  Try converting
it to character.

--- Carla Rebelo <crebelo at liaad.up.pt> wrote:
> Good morning!
> 
> I do not speak English very well and so I will try
> to explain the best I 
> can. I have this:
> 
>  > tabela[,1]
> [1] a a b b a c b a c c c c c
> Levels: a b c
> 
>  >unique(tabela[,1])
> [1] a b c
> Levels: a b c
> 
>  >var<-unique(tabela[,1])[1]
> 
>  > var
> [1] a
> Levels: a b c
> 
> But if I concatenate like this
>  > cat("VAR: ", var, "\n")
> 
> I obtain
>  >VAR:  1
> 
> and I want to obtain
>  >VAR: a
> 
> How can I do this? Thanks!
> 
> ______________________________________________
> 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.
> 


      Looking for the perfect gift? Give the gift of Flickr!