Hello,

I want to build a function to call up a column of a data.frame by the names of 
the columns.  I have column names that are sequentially named (col1, col2, 
etc.). How do I change a character expression into something that will be 
understood as a data.frame column.  For example: 

 example<-data.frame(cbind(col1=1:10, col2=21:30, col3=41:50))
  call.fun<-function(t){
    x<-paste("col",t, sep="")  ## Change this so that it is the data, not a 
character expression
     example$x}

call.fun(t=2)

 Within the real function, I will continue do calculations on the column of 
data.  My problem is that I am either getting a character expression or NULL 
from my function.

Thanks for your help on what is probably a very simple question.

John
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