[R] Efficiently create dummy

What's the neat way to create a dummy from a list? The code below is not replicable, but hopefully self-explanatory... d$treatment-rep(1,length(d)) notreat-c(AR, DE, MS, NY, TN, AK, LA, MD, NC, OK, UT, VA) #i would really like this to work: d$treatment[d$st==any(notreat)]-0 #but instead i

Re: [R] Efficiently create dummy

well, you can first define a factor, and the use model.matrix(), e.g., fc - factor(c(AR, DE, MS, NY)) model.matrix(~ fc) for more info check ?model.matrix(), e.g., if you want to change the contrasts. I hope it helps. Best, Dimitris Rob Denniker wrote: What's the neat way to create a

Re: [R] Efficiently create dummy

On 3/23/2009 5:44 AM, Rob Denniker wrote: What's the neat way to create a dummy from a list? The code below is not replicable, but hopefully self-explanatory... d$treatment-rep(1,length(d)) notreat-c(AR, DE, MS, NY, TN, AK, LA, MD, NC, OK, UT, VA) #i would really like this to work: