Creating a data.frame

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)

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

You don't need to force it! It's not obvious what made you
think of using cbind() internally, but it doesn't do what
you intended. Simply:

  d<-data.frame(x=I(x),y=y,z=z)
  d
#     x y z
# 1 aaa 0 0
# 2 bbb 0 0
# 3 ccc 0 0
  str(d)
# 'data.frame':   3 obs. of  3 variables:
#  $ x:Class 'AsIs'  chr [1:3] "aaa" "bbb" "ccc"
#  $ y: num  0 0 0
#  $ z: num  0 0 0

The trouble was that cbind(x=I(x),y=y,z=z) makes a matrix,
and you cannot mix types in a matrix, so this will coerce
all the variables to character type. So it's your original
way which does the forcing!

Hoping this helps,
Ted.



--------------------------------------------------------------------
E-Mail: (Ted Harding) <Ted.Harding at manchester.ac.uk>
Fax-to-email: +44 (0)870 094 0861
Date: 13-Feb-08                                       Time: 23:24:30
------------------------------ XFMail ------------------------------