[R] Bug in colnames of data.frames?

[David Forrest]

On Tue, 17 Aug 2004, Arne Henningsen wrote:

> Thank you for all your answers!
>
> I agree with you that it is not a bug. My mistake was that I thought that a
> data frame is similar to a matrix, but as ?data.frame says they "... share
> many of the properties of matrices and of lists".
...
>
> I think the current presentation
> > myData
>   var1 var2 var3 xyzzy
> 1    1    5    6     5
> 2    2    6    8     4
> 3    3    7   10     3
> 4    4    8   12     2
>
> is confusing because it is not directly (without another command like str())
> apparent why myData[[ "var1" ]] works fine while myData[[ "xyzzy" ]] does
> not.

In some ways it is a bug -- in the documentation, print.data.frame, or
format.data.frame

Consider assigning a wider dataframe to var4:

myData<-data.frame(matrix(1:12,4),var4=I(data.frame(xyzzy=5:2,plugh=1:4)))
myData  # error
class(myData[["var4"]])<-"data.frame"
myData  # gives indications of sub-variables by var.xyzzy, var.plugh
myData[["var4.plugh"]]  # NULL
myData[["var4"]][["plugh"]]

str(myData)

By the way, is there a way of making such an assignment in one step
without the I() class() hack?

dave
-- 
 Dave Forrest
 drf at vims.edu                                    (804)684-7900w
 drf5n at maplepark.com                             (804)642-0662h
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