cartesian-product

I am having a problem with Hibernate generating invalid SQL. Specifically, mixing and matching implicit and explicit joins. This seems to be an open bug . However, I'm not sure why this is invalid SQL. I have come up with a small toy example that generates the same syntax exception. Schema CREATE TABLE Employee ( employeeID INT, name VARCHAR(255), managerEmployeeID INT ) Data INSERT INTO Employee (employeeID, name) VALUES (1, 'Gary') INSERT INTO Employee (employeeID, name, managerEmployeeID) VALUES (2, 'Bob', 1) Working SQL Both of these queries work. I realize there is a Cartesian product;

I want to have a binary operator cross (cross-product/cartesian product) that operates with traversables in Scala: val x = Seq(1, 2) val y = List('hello', 'world', 'bye') val z = x cross y # i can chain as many traversables e.g. x cross y cross w etc assert z == ((1, 'hello'), (1, 'world'), (1, 'bye'), (2, 'hello'), (2, 'world'), (2, 'bye')) What is the best way to do this in Scala only (i.e. not using something like scalaz)? You can do this pretty straightforwardly with an implicit class and a for -comprehension in Scala 2.10: implicit class Crossable[X](xs: Traversable[X]) { def cross[Y](ys:

I have a list of arrays and I would like to get the cartesian product of the elements in the arrays. I will use an example to make this more concrete... itertools.product seems to do the trick but I am stuck in a little detail. arrays = [(-1,+1), (-2,+2), (-3,+3)]; If I do cp = list(itertools.product(arrays)); I get cp = cp0 = [((-1, 1),), ((-2, 2),), ((-3, 3),)] But what I want to get is cp1 = [(-1,-2,-3), (-1,-2,+3), (-1,+2,-3), (-1,+2,+3), ..., (+1,+2,-3), (+1,+2,+3)]. I have tried a few different things: cp = list(itertools.product(itertools.islice(arrays, len(arrays)))); cp = list

I would like to create a method which creates a stream of elements which are cartesian products of multiple given streams (aggregated to the same type at the end by a binary operator). Please note that both arguments and results are streams, not collections. For example, for two streams of {A, B} and {X, Y} I would like it produce stream of values {AX, AY, BX, BY} (simple concatenation is used for aggregating the strings). So far, I have came up with this code: private static <T> Stream<T> cartesian(BinaryOperator<T> aggregator, Stream<T>... streams) { Stream<T> result = null; for (Stream<T>

I have the following collection type: Map<String, Collection<String>> map; I would like to create unique combinations of each of map.size() from a single value in the collection for each Key. For example suppose the map looks like the following: A, {a1, a2, a3, ..., an} B, {b1, b2, b3, ..., bn} C, {c1, c2, c3, ..., cn} The result I would like to get would a List<Set<String>> result, looking similar to (ordering is not important, it just needs to be a 'complete' result consisting of all possible combinations): {a1, b1, c1}, {a1, b1, c2}, {a1, b1, c3}, {a1, b2, c1}, {a1, b2, c2}, {a1, b2, c3}, .

This question asks how to compute the Cartesian product of a given number of vectors. Since the number of vectors is known in advance and rather small, the solution is easily obtained with nested for loops. Now suppose that you are given, in your language of choice, a vector of vectors (or list of lists, or set of sets, etc.): l = [ [1,2,3], [4,5], [6,7], [8,9,10], [11,12], [13] ] If I was asked to compute its Cartesian product, that is [ [1,4,6,8,11,13], [1,4,6,8,12,13], [1,4,6,9,11,13], [1,4,6,9,12,13], ... ] I would proceed with recursion. For example, in quick&dirty python, def