[R] assign column classes when creating a data frame from several vectors

[jim holtman]

By doing "cbind(ID,TREAT,T1,T2)" you are coercing everything to
character and therefore factors in the dataframe.  Why didn't you just
say:

data<-data.frame(ID,TREAT,T1,T2)


On Jan 29, 2008 9:02 PM, kamokoi <kamokoi at gmail.com> wrote:
>
> R-helpers,
>
> Thanks in advance for your help.  I am an R newbie and I am having trouble
> figuring out the easiest/most efficient way to assign classes to columns in
> a newly created data frame.  R seems to want to convert everything to a
> factor when I use the cbind function to compile vectors into a data frame.
>
> ID<-seq(1,10,1)
> TREAT<-c(rep("B",5),rep("G",5))
> T1<-rnorm(10,50,10)
> T2<-rnorm(10,15,10)
> data<-as.data.frame(cbind(ID,TREAT,T1,T2))
>
> data
>
>   ID TREAT               T1                T2
> 1   1     B  41.506987139726  20.0964019326073
> 2   2     B 53.7814271299636   4.9049787919397
> 3   3     B  54.118333111305  18.2182330777312
> 4   4     B 48.8591282265369  12.4561774992591
> 5   5     B 32.3160291908524  23.6665858869752
> 6   6     G 52.3181626145907 -4.60173207209386
> 7   7     G 53.4170845444393  2.30744010208809
> 8   8     G 60.4200675102018  10.9954680147326
> 9   9     G 42.6264529901835  9.22980548637643
> 10 10     G 40.2748346897501  14.2458580129253
>
> sapply(data,class)
>      ID    TREAT       T1       T2
> "factor" "factor" "factor" "factor"
>
> The only way I can find to get around this is to use stringsAsFactors=FALSE
> and then assign classes to each of the columns individually.
>
> data<-as.data.frame(cbind(ID,TREAT,T1,T2), stringsAsFactors=F)
> data$ID<-as.factor(data$ID)
> data$TREAT<-as.factor(data$TREAT)
> data$T1<-as.numeric(data$T1)
> data$T2<-as.numeric(data$T2)
> sapply(data,class)
>       ID     TREAT        T1        T2
>  "factor"  "factor" "numeric" "numeric"
>
> Is there a more efficient way to do the same thing.
>
> Thanks for your help.
>
>
>
> --
> View this message in context: http://www.nabble.com/assign-column-classes-when-creating-a-data-frame-from-several-vectors-tp15174042p15174042.html
> Sent from the R help mailing list archive at Nabble.com.
>
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> and provide commented, minimal, self-contained, reproducible code.
>



-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem you are trying to solve?