On 2011-05-18 12:12, John Poulsen wrote:
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$x}
call.fun(t=2)
Get out of the dollar habit.
Replace your
example$x
with
example[[x]]
or with
example[, x]
Peter Ehlers
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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