Summary(2): how to generate the sequence

[Ning Li <lin@cryptic.rch.unimelb.edu.au>]

Dear lister,

Many thanks to Thomas Jagger Phd from Insightful Corporation.
He contributed one more method to create a sequential id.  

The three types of methods we have had so far are:

  1) -rep(1:n, each=k)-  
      where n=unique(id), k=# of repeated
measures each id

  2)  -as.numeric(as.factor(id))-

  3)  -match(id,unique(id))-

The argument -each- in -rep()- is usually a constant, meaning that 
method 1) works if all id were observed for the same number of 
times (no missing values in a balanced design).  The 2) and 3) 
are more general in this sense. 


Best Regards

-------------------------------------------------------------------
Ning Li
Research Assistant, CEBU  Univ. of Melbourn