Cartesian product of two or more lists
This page is the answer to the task Cartesian product of two or more lists in the Rosetta Code.
Contents
Description (from Rosetta Code)
Task
Show one or more idiomatic ways of generating the Cartesian product of two arbitrary lists in your language. Demonstrate that your function/method correctly returns: {1, 2} × {3, 4} = {(1, 3), (1, 4), (2, 3), (2, 4)} and, in contrast: {3, 4} × {1, 2} = {(3, 1), (3, 2), (4, 1), (4, 2)} Also demonstrate, using your function/method, that the product of an empty list with any other list is empty. {1, 2} × {} = {} {} × {1, 2} = {} For extra credit, show or write a function returning the n-ary product of an arbitrary number of lists, each of arbitrary length. Your function might, for example, accept a single argument which is itself a list of lists, and return the n-ary product of those lists. Use your n-ary Cartesian product function to show the following products: {1776, 1789} × {7, 12} × {4, 14, 23} × {0, 1} {1, 2, 3} × {30} × {500, 100} {1, 2, 3} × {} × {500, 100} |
Program
No programs needed. Cartesian product is intrinsically supported in Fōrmulæ.
Case 1. No commutativity
Case 2. With an empty list
Case 3. Extra credit. n-ary cartesian product
Additional case. Cartesian product exponentiation
In a n-ary cartesian product of lists, the lists are the same, then the cartesian product exponentiation can be used: