[R] creating dummy with loop command

[David Winsemius]

On Apr 23, 2010, at 11:26 AM, serdal ozusaglam wrote:

>
> Dear R users,
>
> I have a simple question (probably) but i couldnt how to find a  
> solution for that.
>
> i am using 2 digit industry codes and 3 digit industry codes for my  
> model, and i need to create dummies for the industries. The case is  
> simple for the 2-digit industries since there are not that mcuh of  
> them, so i am creating my dummies as following
> ind_2da<-(ind_2d==11)#for the 11th industry
> ind_2dc<-(ind_2d==12)#for the 12th industry and so on so forth ...  
> then i directly put the dummy into the regression which works well.
>
> but creating dummies for the 3-digit is rather complicated since  
> there are alot of sub-industries, for example:111,112,113...119 and  
> this is just for the 11th industry
> so when i consider the codes continues till 40, it would be  
> exhausting to do it by hand.
>
> so i was looking for the loop commands to do it faster but since i  
> am a newbie i got lost in it.
>
> so is there some one who can help me for this problem?

Don't use dummies.

?factor

>
-- 

David Winsemius, MD
West Hartford, CT