[R] Creating Dummy Variables in R

[whitaker m. (mw1006)]

Hi,
I am trying to create a set of dummy variables to use within a multiple linear regression and am unable to find the codes within the manuals.

For example i have:
Price     Weight     Clarity
                             IF      VVS1    VVS2
500        8             1         0          0
1000      5.2          0         0          1
864        3              0        1          0
340        2.6          0         0          1
90          0.5          1         0          0 
450        2.3          0         1          0

Where price is dependent upon weight (single value in each observation) and clarity (split into three levels, IF, VVS1, VVS2).
I am having trouble telling the program that clarity is a set of 3 dummy variables and keep getting error messages, what is the correct way?

Any helps is greatly appreciated.
Matthew