[R] SAS to R migration questions

Fernando Henrique Ferraz P. da Rosa mentus at gmx.de
Sun Sep 12 23:06:39 CEST 2004

Matthew Wilson writes:
> (...)
> Step 3:
> I print a list of number of sales per customer ID, ranking the customer
> IDs from most to least.  I use a SAS proc freq step for this:
>     proc freq data=d2 order=freq;
>         tables custid;
>     run;
> and the output would look like this:
>     custid      freq
>     111         2
>     112         1
> Again, I have no idea how to do step 3 in R.  

        Provided that you are going to work with this data stored in a
SQL database, it'll probably be more efficient to do this sort of
manipulation directly in SQL. Anyways, the following lines of code in R
will do what you described:

cust <- c(111,111,112)
cc <- data.frame(t(sapply(unique(cust),function(level,vec) {
c(custid=level,freq=sum(vec==level)) },cust))) 


Fernando Henrique Ferraz P. da Rosa

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