[R] collating columns

[Liaw, Andy]

Here's one possible way (assuming the two data frames have the same number
of columns):

> d1 <- data.frame(A=1, B=2, C=3)
> d2 <- data.frame(X=1, Y=2, Z=3)
> res <- c(d1, d2)  # This cbind them and turn into a list.
> idx <- as.vector(matrix(1:(2 * ncol(d1)), 2, byrow=TRUE))
> idx
[1] 1 4 2 5 3 6
> as.data.frame(res[idx])
  A X B Y C Z
1 1 1 2 2 3 3

HTH,
Andy

From: Matthew Scholz
> 
> Dumb newbie question: I've searched the manual, R help and 
> the mailing list
> archives, but can't seem to find the answer to this simple 
> problem that I
> have. If I have a series of columns in a dataframe: (A, B, C 
> ...) and I want
> to merge them with another series of columns (Z,Y,X ...) such that the
> resulting data frame has columns A,Z,B,Y,C,X ..., how do I do 
> this? In other
> words, I'm trying to collate two column sets (for purposes of 
> writing a
> presentable file) rather than simply using cbind to add one 
> set of columns
> onto the end of another set.
> 
> Thanks in advance of your help.
> 
> Matt
> --
> Matt Scholz
> Senior Research Specialist
> Department of Plant Sciences
> University of Arizona
> (520) 621-1695
> 
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