[R] Recode factor into binary factor-level vars

[soeren.vogel at eawag.ch]

How to I "recode" a factor into a binary data frame according to the  
factor levels:

### example:start
set.seed(20)
l <- sample(rep.int(c("locA", "locB", "locC", "locD"), 100), 10,  
replace=T)
# [1] "locD" "locD" "locD" "locD" "locB" "locA" "locA" "locA" "locD"  
"locA"
### example:end

What I want in the end is the following:

m$locA: 0, 0, 0, 0, 0, 1, 1, 1, 0, 1
m$locB: 0, 0, 0, 0, 1, 0, 0, 0, 0, 0
m$locC: 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
m$locD: 1, 1, 1, 1, 0, 0, 0, 0, 1, 0

Instead of 0, NA's would also be fine.

Thanks, Sören

-- 
Sören Vogel, PhD-Student, Eawag, Dept. SIAM
http://www.eawag.ch, http://sozmod.eawag.ch