prd (product function)
The aggregate function prd returns the product of the items in its argument.
If the argument is an atom, it is returned unchanged.
Otherwise, if the argument is a numeric list, it returns the product as an atom. A null is treated as 1.
If the argument is a non-numeric list, a type error is signaled.
q)prd 7 / product of atom (returned unchanged) 7 q)prd 2 3 5 7 / product of list 210 q)prd 2 3 0N 7 / 0N is treated as 1 42 q)prd (1 2 3 4;2 3 5 7) / product of list of lists 2 6 15 28 q)prd "abc" 'type
For a complete list of functions, see the kdb+ Function Reference.