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changing names of vectors in list or data.frame

3 messages · Clint Harshaw, Brian Ripley, Peter Dalgaard

Original
Clint Harshaw
# 
When I combine separate vectors into one list, there are new names 
created. I'd like to change them to something more meaningful.

Here are two examples using data(zelazo) from library(ISwR):

 > library(ISwR)
 > data(zelazo)
 > attach(zelazo)
 > zelazo
$active
[1]  9.00  9.50  9.75 10.00 13.00  9.50

$passive
[1] 11.00 10.00 10.00 11.75 10.50 15.00

$none
[1] 11.50 12.00  9.00 11.50 13.25 13.00

$ctr.8w
[1] 13.25 11.50 12.00 13.50 11.50
 > walk <- stack(list("active"=active, "passive"=passive, "none"=none, 
"ctr.8w"=ctr.8w))
 > walk
    values     ind
1    9.00  active
[...rows deleted...]
23  11.50  ctr.8w

I want to name the first column "walking" and the second column 
"training". How do I do this?

Here is a second example:

 > walk2 <- data.frame(c(active, passive, none, ctr.8w), c(rep(1:4, 
c(length(active), length(passive), length(none), length(ctr.8w)))))
 > walk2
    c.active..passive..none..ctr.8w.
1                              9.00
[...rows deleted...]
23                            11.50
 
c.rep.1.4..c.length.active...length.passive...length.none...length.ctr.8w....
1 
        [...rows deleted...]
4
 >

The created names are very long. Again, I want the name of the first 
column to be "walking" and the second column to be "training".

Thanks,
Clint
Brian Ripley
# 
1) use names() on the resulting data frame: stack() always uses those two 
names.  As in

names(walk) <- c("walking", "training")

2) data.frame is more useful when the arguments are named, and you can 
just name them: see the help.
On Sun, 19 Feb 2006, Clint Harshaw wrote:

            

      
      
      
    

        

      
      
    

        

  
    

      
      
    

  


  


      

    

    

      
      

        


  

        

      Peter Dalgaard
    

    

      
      #
    

  


  

      
Clint Harshaw <charshaw at presby.edu> writes:

            

      
      
      
    

        
The obvious way would seem to be

names(walk) <- c("walking","training")

            

      
      
      
    

        
walk2 <- data.frame(walking=c(active, passive, none, ctr.8w),
   training=c(rep(1:4, c(length(active), length(passive),
   length(none), length(ctr.8w)))))


[or 
 walk2 <- data.frame(walking=unlist(zelazo),
                     training=factor(rep(1:4, sapply(zelazo,length)),
                                     labels=names(zelazo) ))
]