On Dec 3, 2010, at 4:14 AM, Keith Jewell wrote:
or even shorter
df[,paste("A","C",sep="")]
Other grepping methods that generalize better to partial matches:
df[ , grep("^AC$", colnames(df))]
df[ grep("^AC$", colnames(df)) ]
--
David.
"Santosh Srinivas" <[email protected]> wrote in message
news:[email protected]...
try this ..
df[,colnames(df)==paste("A","C",sep="")]
On Fri, Dec 3, 2010 at 12:05 PM, Yuan Jian <[email protected]>
wrote:
Hello,
I tried to use a variable to refer colname, but I got error, could
anyone
give me advice?
df=data.frame(cbind(AB=1:3,AC=3:5))
df$AC
[1] 3 4 5
df$paste("A","C",sep="")
Error: attempt to apply non-function
thanks
Jian
David Winsemius, MD
West Hartford, CT
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