Thank you very much. I want each element of zz by each element of tt (i.e., every possible 2-way combination). -- View this message in context: http://r.789695.n4.nabble.com/How-to-calculate-the-product-of-every-two-elements-in-two-lists-tp3593832p3593941.html Sent from the R help mailing list archive at Nabble.com.