How to calculate the Cartesian product of two vectors?

Question

Is there an efficient method to calculate the Cartesian product of two vectors in DolphinDB?

For example, given the vectors ['aa', 'bb'] and ['cc', 'dd'], the desired result is ['aacc', 'aadd', 'bbcc', 'bbdd'] without regard for the order. Your suggestions will be highly appreciated!

Answer 1

vec1 = ['aa', 'bb'];
vec2 = ['cc', 'dd'];
result = cross(vec1, vec2);

result will contain ['aacc', 'aadd', 'bbcc', 'bbdd']

Answer 2

These two pages refer to the same thing (cross joins):

https://dolphindb.com/help/SQLStatements/TableJoiners/crossjoin.html?highlight=cartesian

https://dolphindb.com/help/FunctionsandCommands/FunctionReferences/c/cj.html?highlight=cartesian

Example using cj()

a = table(2010 2011 2012 as year)
b = table(`IBM`C`AAPL as Ticker);
cj(a,b);

Result

year  Ticker
2010  IBM
2010  C
2010  AAPL  
2011  IBM
2011  C
2011  AAPL  
2012  IBM
2012  C
2012  AAPL  

Try this

a = table(aa bb as x)
b = table(cc dd as y);
cj(a,b);