R-alpha: list assignment

Peter Dalgaard BSA writes:

Robert Gentleman <rgentlem@stat.auckland.ac.nz> writes:

Peter,
They don't work on purpose. Basically this is the same problem as indexing
beyond the end of an array. In almost all cases it is an error.
To add a variable with a specific name to a data frame how about

x (the dataframe)
var1 the variable
name1 the name

x<-cbind(x,var1)
names(x)[ncol(x)]<-name1

Hm. Not sure about that argument. After all we don't protect against
typing

x$mumble<-17
instead of 
x$grumble<-17

Once you're into indexing lists through character variables, shouldn't
you be assumed to know what you're doing? Beginners can do much more
mischief with e.g. dfr$new<-0 which will turn dfr into a list.

However, apropos your construct, watch this:

x<-list()
x[[1]]<-23
names(x)[1]<-"a"
x

$"a"
[1] 23

unlist(x)

\"a\" 
   23 

names(x)[1]     

[1] "\"a\""

names(x)   

[1] "\"a\""

names(x)[1]<-"a"
names(x)

[1] "a"

x

$a
[1] 23

unlist(x)

 a 
23