[R] Odp: Creating a data.frame

[Petr PIKAL]

Hi

r-help-bounces at r-project.org napsal dne 13.02.2008 23:17:32:

> OK...newbie question here.
> Either I'm reading the docs wrong, or I'm totally confused.
> 
> Given the following:
> 
> x<-c("aaa","bbb","ccc")
> y<-rep(0,3)
> z<-rep(0,3)
> 
> is.character(x)
> [1] TRUE
> 
> is.numeric(y)
> [1] TRUE
> 
> Now...I want to create a data frame, but keep the data types.
> In reading the docs, I assume you do it this way:
> 
> d<-data.frame(cbind(x=I(x),y=y,z=z)

cbind creates a matrix which has to have all values the same type, in your 
case character.

d<-data.frame(x=x,y=y,z=z)

will do what you want. Try to find out differences among various types of 
objects, its pros and cons from some intro documents.

Regards

Petr

> 
> But, when I do str(d), I get the following:
> 
> 'data.frame':   3 obs. of  3 variables:
>   $ x: Factor w/ 3 levels "aaa","bbb","ccc": 1 2 3
>   $ y: Factor w/ 1 level "0": 1 1 1
>   $ z: Factor w/ 1 level "0": 1 1 1
> 
> I thought the I() prevents character from becoming factors, right?
> Secondly, how do I force y and z in the data frame to become numeric?
> 
> Thanks in advance
> Joe
> 
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