[R] Reorder data frame columns by negating list of names

[Thompson, David (MNR)]

Hello,

I would like to reorder columns in a data frame by their names as
demonstrated below:

Take this data frame:
	> xxx <- data.frame(matrix(1:40, ncol=8))
	> names(xxx) <- letters[1:8]
	> xxx
	  a  b  c  d  e  f  g  h
	1 1  6 11 16 21 26 31 36
	2 2  7 12 17 22 27 32 37
	3 3  8 13 18 23 28 33 38
	4 4  9 14 19 24 29 34 39
	5 5 10 15 20 25 30 35 40

and reorder the columns like this:
	> xxx[,c( c('b', 'd', 'h'), c('a', 'c', 'e', 'f', 'g') )]
	   b  d  h a  c  e  f  g
	1  6 16 36 1 11 21 26 31
	2  7 17 37 2 12 22 27 32
	3  8 18 38 3 13 23 28 33
	4  9 19 39 4 14 24 29 34
	5 10 20 40 5 15 25 30 35

where I only have to name the columns that I'm interested in moving to
the first few positions, something like:
	> xxx[,c( c('b', 'd', 'h'), -c('b', 'd', 'h') )]
	Error in -c("b", "d", "h") : invalid argument to unary operator

Suggestions? and Thank you, DaveT.
*************************************
Silviculture Data Analyst
Ontario Forest Research Institute
Ontario Ministry of Natural Resources
david.john.thompson at ontario.ca
http://ofri.mnr.gov.on.ca