[R] Joining two (or more) frequency tables

Hi, I am still new to R and have, in spite of searching all over, found no "understandable" documentation for how to join two (or more) frequency tables. Why would I want to do that and what do I mean by "joining" ? Let me try to explain: I have a diagnosis form that allows registration of up t

[R] SQL-select using native R methods ?

Hi I have a problem in R that I have been trying to solve but without success. I am trying to join two tables on two variables : an ID and a date (optional) that will be common between the two tables In SQL (and SAS PROC SQL) I am a frequent user of the "select" command and I am used to the fol