On Feb 24, 2011, at 1:23 PM, Changbin Du wrote:
HI, Dear R community,
I try to create 100 dummy variables like the following:
ack$id_1 <- (ack$ID==1)*1
ack$id_2 <- (ack$ID==2)*1
..
.
ack$id_100 <- (ack$ID==100)*1
I used the following codes:
for(i in 1:100){
ack$id_[i] <- (ack$ID==i)*1
You are creating only one new column named ack$id_
Putting the "[" operator with a numeric argument after does not name a
new column.
}
But only one column is created, can anyone help me?
If I tell you how to do that I would only be hurting you. You should
be using factors. The modeling functions should all be capable of
accepting them and if you are writing your own then it seems only
sensible that you follow their example.
--
David Winsemius, MD
West Hartford, CT
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