[R] use of variable labels

[Spencer Graves]

 > tst.df <- data.frame(a=letters[1:3], b=factor(c(3:5)))
 > tst.df
   a b
1 a 3
2 b 4
3 c 5
 > as.numeric(tst.df$a)
[1] 1 2 3
 > as.numeric(tst.df$b)
[1] 1 2 3
 > as.character(tst.df$b)
[1] "3" "4" "5"
 > as.numeric(as.character(tst.df$b))
[1] 3 4 5
Does this answer your question?
Spencer Graves

janet rosenbaum wrote:
> The R documentation for some of the foreign package's functions says 
> that the set of variable labels becomes attributes in the resulting
> data frame.  
> 
> Thus, e.g., 5="strongly agree", 4="agree", etc.
> 
> I'm happy that the labels are being passed, but unfortunately, when 
> R summarizes the data, it will list it only as categories, and
> doesn't deal with the corresponding numbers.  It seems as though 
> the numbers attached to the categories don't exist.  
> 
> Is there a way to make R go back and forth between the categories and 
> the corresponding numbers as Stata does, or do I just have to set
> convert.factors=FALSE ?
> 
> Hope everyone's enjoying the April snow!
> Thanks,
> 
> Janet
> 
> 
>>MC<-read.dta("C:/Documents and Settings/janet/Desktop/poleff/mexchn_gary.dta")
>>summary(MC)
> 
>        id             country              code         sex     
>  Min.   :10100001   Length:1068        Mexico:604   Female:541  
>  1st Qu.:10100306   Mode  :character   China :464   Male  :509  
>  Median :14000071                                   NA's  : 18  
>  Mean   :12305905                                               
>  3rd Qu.:14000339                                               
>  Max.   :14000628                                               
> 
>>mean(MC$id)
> 
> [1] 12305905
> 
>>mean(MC$sex)
> 
> [1] NA
> Warning message: 
> argument is not numeric or logical: returning NA in: mean.default(MC$sex) 
> 
> 
> 
> Stata gives:
> 
> . summ
> 
>     Variable |     Obs        Mean   Std. Dev.       Min        Max
> -------------+-----------------------------------------------------
>           id |    1068    1.23e+07    1934101   1.01e+07   1.40e+07
>      country |       0
>         code |    1068    .4344569   .4959177          0          1
>          sex |    1050    1.484762   .5000059          1          2
> 
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