R help - Sep 2007 - enable object name to be called as object (a dataset)

What I am trying to do is as follows:

- I have listed names of all wanted objects (datasets A,B,C... ) in current
workspace as a vector: 

obj <- c('A','B','C')

- then i need to use these objects, say to extract all the 1st columns and
bind to an existing dataset ('data'): 
 
for ( i in 1:3){
newdata <- obj[i] 
data <- cbind(data,newdata [[1]] )
}

Obviously, it doesn't work since obj[i] is just a string of dataset name.
Here is my question: how to call it as a original dataset? Thanks.
-- 
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"get" might be good enough for you:
> a <- 10
> name <- "a"
> get("a")
[1] 10
> get(name)
[1] 10
>
Gabor

On Fri, Sep 07, 2007 at 02:42:07PM -0700, runner wrote:
> 
> What I am trying to do is as follows:
> 
> - I have listed names of all wanted objects (datasets A,B,C... ) in current
> workspace as a vector: 
> 
> obj <- c('A','B','C')
> 
> - then i need to use these objects, say to extract all the 1st columns and
> bind to an existing dataset ('data'): 
>  
> for ( i in 1:3){
> newdata <- obj[i] 
> data <- cbind(data,newdata [[1]] )
> }
> 
> Obviously, it doesn't work since obj[i] is just a string of dataset
name.
> Here is my question: how to call it as a original dataset? Thanks.
> -- 
> View this message in context:
http://www.nabble.com/enable-object-name-to-be-called-as-object-%28a-dataset%29-tf4403933.html#a12563767
> Sent from the R help mailing list archive at Nabble.com.
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
-- 
Csardi Gabor <csardi at rmki.kfki.hu>    MTA RMKI, ELTE TTK

This should work:

do.call(cbind, lapply(1:length(obj), function(i) get(obj[i])[,1]))

Best,
Giovanni
> Date: Fri, 07 Sep 2007 14:42:07 -0700 (PDT)
> From: runner <sunnyside500 at gmail.com>
> Sender: r-help-bounces at stat.math.ethz.ch
> Precedence: list
> 
> 
> What I am trying to do is as follows:
> 
> - I have listed names of all wanted objects (datasets A,B,C... ) in current
> workspace as a vector: 
> 
> obj <- c('A','B','C')
> 
> - then i need to use these objects, say to extract all the 1st columns and
> bind to an existing dataset ('data'): 
>  
> for ( i in 1:3){
> newdata <- obj[i] 
> data <- cbind(data,newdata [[1]] )
> }
> 
> Obviously, it doesn't work since obj[i] is just a string of dataset
name.
> Here is my question: how to call it as a original dataset? Thanks.
> -- 
> View this message in context:
http://www.nabble.com/enable-object-name-to-be-called-as-object-%28a-dataset%29-tf4403933.html#a12563767
> Sent from the R help mailing list archive at Nabble.com.
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
> 
> 
-- 

Giovanni Petris  <GPetris at uark.edu>
Associate Professor
Department of Mathematical Sciences
University of Arkansas - Fayetteville, AR 72701
Ph: (479) 575-6324, 575-8630 (fax)
http://definetti.uark.edu/~gpetris/

a <- 1:3
b <- 11:13
c <- 21:23

names <- c('a','b','c')

do.call(data.frame, list(sapply(names, function(x) get(x))))



runner wrote:
> 
> What I am trying to do is as follows:
> 
> - I have listed names of all wanted objects (datasets A,B,C... ) in
> current workspace as a vector: 
> 
> obj <- c('A','B','C')
> 
> - then i need to use these objects, say to extract all the 1st columns and
> bind to an existing dataset ('data'): 
>  
> for ( i in 1:3){
> newdata <- obj[i] 
> data <- cbind(data,newdata [[1]] )
> }
> 
> Obviously, it doesn't work since obj[i] is just a string of dataset
name.
> Here is my question: how to call it as a original dataset? Thanks.
> 
-- 
View this message in context:
http://www.nabble.com/enable-object-name-to-be-called-as-object-%28a-dataset%29-tf4403933.html#a12564175
Sent from the R help mailing list archive at Nabble.com.