[R] How do I construct a one matrix from another? (newbie)

Apologies if this is an obvious question but I am teaching myself R and the occasional push in the right direction is much appreciated? I have a data.frame containing data that looks like this CustID itemID 1a 1b 2c 3a 3c I want to assemble the vector of

[R] Help deciding on data format for sales data (newbie)

Dear All Beginning data mining and need some help working out the best way to represent data. I have searched here and online and not found any real help. Imagines that I have a file of order(sales) data OrderNo CustomerNo ItemsInOrder 1 1a,b,c 2 1