[R] changing names of vectors in list or data.frame

[Peter Dalgaard]

Clint Harshaw <charshaw at presby.edu> writes:

> 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?

The obvious way would seem to be

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

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) ))
]
-- 
   O__  ---- Peter Dalgaard             Øster Farimagsgade 5, Entr.B
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