[R] Referencing data frames

[Steven McKinney]

Hi Payam,

Here's a basic example using pointless
data frames and an otherwise useless
function to illustrate the issues you
want 

> ## Fresh R session with nothing yet defined
> foo <- data.frame(matrix(1:12, ncol = 3))
> bar <- data.frame(matrix(101:112, ncol = 3))
> 
> objects()
[1] "bar" "foo"
> 
> myrbind <- function(names) {
+   df1 <- get(names[1])
+   df2 <- get(names[2])
+   dfrbind <- rbind(df1, df2)
+   dfrbind.name <- paste(names, collapse = ".")
+   assign(dfrbind.name, dfrbind, pos = 1)
+   invisible()
+ }
> 
> dfnames <- c("foo", "bar", "baz")
> myrbind(dfnames)
> objects()
[1] "bar"         "dfnames"     "foo"         "foo.bar.baz" "myrbind"    
> foo.bar.baz
   X1  X2  X3
1   1   5   9
2   2   6  10
3   3   7  11
4   4   8  12
5 101 105 109
6 102 106 110
7 103 107 111
8 104 108 112
> 


HTH


Steven McKinney, Ph.D.

Statistician
Molecular Oncology and Breast Cancer Program
British Columbia Cancer Research Centre

email: smckinney +at+ bccrc +dot+ ca

tel: 604-675-8000 x7561

BCCRC
Molecular Oncology
675 West 10th Ave, Floor 4
Vancouver B.C. 
V5Z 1L3
Canada




-----Original Message-----
From: r-help-bounces at r-project.org on behalf of Payam Minoofar
Sent: Fri 6/12/2009 3:00 PM
To: r-help at r-project.org
Subject: [R] Referencing data frames
 
Hi,

How do I use the string content of a string variable to reference a data frame of the same name? I want to do the typical tasks of 1) building a name with a string variable and using the string variable to create a data frame (or any object) whose name is the string value of the variable and 2) pass on a string to a function as a parameter, and then use that string to refer to an existing data frame.

Thanks in advance.

Payam
--
Payam Minoofar, Ph.D.
Scientist
Meissner Filtration Products
4181 Calle Tesoro
Camarillo, CA 93012
USA
+1 805 388 9911
+1 805 388 5948 fax
Payam.minoofar at meissner.com


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