R help - Aug 2006 - prefixing list names in print

With

print(list(A="a",B="b"))

it displays

$A
[1] "a"

$B
[1] "b"

I would like to add a common prefix to all the list tags after the $. 
Pasting the prefix to the "names" does not work (appear after the $). 
For example if the prefix would be "P", it should display:

P$A
[1] "a"

P$B
[1] "b"

I tried to add a "name" attribute to the list or to add a
prefix="P" to
print but nothing works. Any hint?

Thanks,

	Laurent.

Laurent Deniau wrote:
> With
> 
> print(list(A="a",B="b"))
> 
> it displays
> 
> $A
> [1] "a"
> 
> $B
> [1] "b"
> 
> I would like to add a common prefix to all the list tags after the $. 
> Pasting the prefix to the "names" does not work (appear after the
$).
> For example if the prefix would be "P", it should display:
> 
> P$A
> [1] "a"
> 
> P$B
> [1] "b"
> 
> I tried to add a "name" attribute to the list or to add a
prefix="P" to
> print but nothing works. Any hint?
This is a very internal feature of print(). At a first quick look, I 
think you will have to change the R sources and recompile.
Conclusion: Don't do it.

Uwe Ligges



> Thanks,
> 
> 	Laurent.
> 
> ______________________________________________
> 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.

On Tue, 8 Aug 2006, Laurent Deniau wrote:
> With
> 
> print(list(A="a",B="b"))
> 
> it displays
> 
> $A
> [1] "a"
> 
> $B
> [1] "b"
> 
> I would like to add a common prefix to all the list tags after the $.
`prefix' ... `after'?  You seem to want to prefix component names: why?
What do you want for component $a$b$c?  For unnamed components?
 
> Pasting the prefix to the "names" does not work (appear after the
$).
> For example if the prefix would be "P", it should display:
> 
> P$A
> [1] "a"
> 
> P$B
> [1] "b"
> 
> I tried to add a "name" attribute to the list or to add a
prefix="P" to
> print but nothing works. Any hint?
You will need to alter the C code to do this.

-- 
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

A simple function will do what you want, customize this as needed:
lprint <- function(lst,prefix)
{
for (i in 1:length(lst)) {
  
cat(paste(prefix,"$",names(lst)[i],sep=""),"\n")
   print(lst[[i]])
   cat("\n")
}
}
P <- list(A="a",B="b")
lprint(P,"Prefix")

> -----Original Message-----
> From: r-help-bounces at stat.math.ethz.ch
> [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Laurent Deniau
> Sent: Tuesday, August 08, 2006 12:25 PM
> To: R-help
> Subject: [R] prefixing list names in print
>
> With
>
> print(list(A="a",B="b"))
>
> it displays
>
> $A
> [1] "a"
>
> $B
> [1] "b"
>
> I would like to add a common prefix to all the list tags after the $.
> Pasting the prefix to the "names" does not work (appear after the
$).
> For example if the prefix would be "P", it should display:
>
> P$A
> [1] "a"
>
> P$B
> [1] "b"
>
> I tried to add a "name" attribute to the list or to add a
> prefix="P" to
> print but nothing works. Any hint?
>
> Thanks,
>
> 	Laurent.
>
> ______________________________________________
> 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.
>