Hi Richard, See my project DynamicMatrixExample, in Examples of Gambas Software Farm
Regards Gianluigi 2017-02-07 0:30 GMT+01:00 Tobias Boege <tabo...@gmail.com>: > On Mon, 06 Feb 2017, Riccardo wrote: > > Hi, > > > > Is it possible to use the array.sort() method on a two-dimensional array? > > > > > > > > > > > > > Public arr_Response As New String[][] > > > > > > > > > > > > > Specifically, I'd like to sort the entire array based on the contents of > the second column something like: arr_Response[][1].sort() ... > > > > You can call String[][].Sort() but the result will probably not be what you > expect. First of all, you have to understand how Gambas handles the type of > multi-dimensional array you're using. I have given more explanations of > this > on this list and elsewhere than I can recount, but I'll do it another time. > (I'll type it out anew; search the mailing list archive if you want to see > previous versions of the explanation.) > > The Gambas interpreter can derive array data types from any given data type > at runtime. Say "X" is any data type that's currently known to the > interpreter > (at runtime), then, if you use "X[]" like a data type in your Gambas code, > the interpreter will notice that "X[]" is made of the known data type "X" > and a pair of brackets and use a code template to create and register a new > data type, which is "array of X". "X[]" is a data type created on the fly > for storing an array of objects of type "X". > > The type "String[]" is built-in into the interpreter, but if you use > "String[][]", the mechanics desribed above are invoked. "String[][]" is a > new data type created from a code templates stored inside the interpreter. > This template is, if you care to look at the sources, is really just > reusing > the methods of the "Object[]" class. > > This means "String[][]" is an "Object[]" which expects to contain elements > of type "String[]" -- nothing more. This finally explains why > String[][].Sort() does not do anything sensible. Since the Sort() method > comes directly from the "Object[]" class, the sorting is done by comparing > memory addresses of the "String[]" elements. It does not look at the > Strings > one layer further down. > > So what about your problem? I would advise that you ditch the String[]. > Define a new class "MyResponse" or something, so that you can declare your > array as > > Public arr_Response As New MyResponse[] > > The advantage is that in your own MyResponse class you can implement the > _compare() special method [1] to compare two MyResponse objects by using > the second field in the response array, as you originally intended. > > After you implement the _compare() method, the Response[].Sort() method > will sort properly. See also this old project [2] in German, where we > demonstrate how to sort GridViews (vastly generic, but with some > restrictions) > using the very same method. There, the column at which to sort can be > specified at runtime. Note that the version of the project on this site > uses a *bad practice* of inheriting Variant[] instead of creating your > own class. (There may be other shortcomings in that project which I don't > remember off-hand.) > > Regards, > Tobi > > [1] http://gambaswiki.org/wiki/lang/special/compare > [2] http://www.gambas-buch.de/dw/doku.php?id=k17:k17.7:k17.7.4:start > > -- > "There's an old saying: Don't change anything... ever!" -- Mr. Monk > > ------------------------------------------------------------ > ------------------ > Check out the vibrant tech community on one of the world's most > engaging tech sites, SlashDot.org! http://sdm.link/slashdot > _______________________________________________ > Gambas-user mailing list > Gambas-user@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/gambas-user > ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, SlashDot.org! http://sdm.link/slashdot _______________________________________________ Gambas-user mailing list Gambas-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/gambas-user
