[R] select columns from vector of column names

[Horace Tso]

How about

data[,colnames(data)%in%colnames] 


-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On Behalf Of Jonathan Flowers
Sent: Friday, July 09, 2010 11:27 AM
To: r-help at r-project.org
Subject: [R] select columns from vector of column names

Hi

I want to extract columns from a data frame using a vector with the desired
column names.

This short example uses the select argument in the subset function to
accomplish what I am trying to do.  Is there a better solution?

#names of desired columns
colnames <- c("col1","col3")

#my data
data <- data.frame("col1"=c(1,2,3),"col2"=c("A","B","C"),"col3"=c(4,5,6))

fun <- function(colname,dframe){
nframe <- subset(dframe,select=colname)
    vec <- nframe[,1]
    return(vec)
}

fun(colnames[1],data)
fun(colnames[2],data)

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