R help - Mar 2010 - Converting a character string into a data frame name and performing assignments to that data frame

Hi,

I would like to do the following operations:

variable.df is a character string that contains the name of the data
frame that I want to do the following operations on:

variable.df <- data.frame();
# I can do the above command using
assign( variable.df, data.frame() )

How can I perform the assignment statements below ?

colnames(variable.df) = colnames(some.other.df)
variable.df = rbind(variable.df, some.other.df)
write.table(variable.df, file=some.file)

Doing
eval(  substitute( colnames(var), list(var=as.name(variable.df) ) ) )
 didn't get me all the way there.

Thanks!
Kavitha

Kavitha Venkatesan-2 wrote:
> 
> variable.df is a character string that contains the name of the data
> frame that I want to do the following operations on:
> 
> variable.df <- data.frame();
> # I can do the above command using
> assign( variable.df, data.frame() )
> 
> How can I perform the assignment statements below ?
> 
> colnames(variable.df) = colnames(some.other.df)
> 
Try to avoid assign and eval when you are not fiRm; the first is rarely
used, and the second is a bit to powerful for safeR.

data(iris)
head(iris)
names(iris) =
c("A","B","C","D","Spec")
head(iris)

Dieter







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Hi,
I'd greatly appreciate any insight into the problem in my previous
message below: Please note that I would like to loop through the
following steps for a list of data frames whose names are dynamically
assigned at run time, so I have a character string variable, called
"variable.df", which stores the name of the data frame at any given
point ...and I need to be able to manipulate the contents of the data
frame somehow using this character string :
> colnames(variable.df) = colnames(some.other.df)
> variable.df = rbind(variable.df, some.other.df)
> write.table(variable.df, file=some.file)
Thanks!
Kavitha

On Sat, Mar 20, 2010 at 5:07 PM, Kavitha Venkatesan
<kavitha.venkatesan at gmail.com> wrote:
> Hi,
>
> I would like to do the following operations:
>
> variable.df is a character string that contains the name of the data
> frame that I want to do the following operations on:
>
> variable.df <- data.frame();
> # I can do the above command using
> assign( variable.df, data.frame() )
>
> How can I perform the assignment statements below ?
>
> colnames(variable.df) = colnames(some.other.df)
> variable.df = rbind(variable.df, some.other.df)
> write.table(variable.df, file=some.file)
>
> Doing
> eval( ?substitute( colnames(var), list(var=as.name(variable.df) ) ) )
> ?didn't get me all the way there.
>
> Thanks!
> Kavitha
>