# f(x, y) or Table

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## f(x, y) or Table

 Greetings, I find a lot of my data needs two indices, f(x,y) instead of one, f(x). f(x) would be implemented easily with a Dictionary, but how do you implement f(x,y)? I guess this is another way of asking is there a Table object or a Tuple object, of even a graphics object Screen that has x,y coordinates with a value? Sincerely, Joe. _______________________________________________ Beginners mailing list [hidden email] http://lists.squeakfoundation.org/mailman/listinfo/beginners
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## Re: f(x, y) or Table

 _______________________________________________ Beginners mailing list [hidden email] http://lists.squeakfoundation.org/mailman/listinfo/beginners
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## Re: f(x, y) or Table

 ???? > On Apr 13, 2016, at 8:15 PM, jelena [via Smalltalk] <[hidden email]> wrote: > > > _______________________________________________ > Beginners mailing list > [hidden email] > http://lists.squeakfoundation.org/mailman/listinfo/beginners> > > If you reply to this email, your message will be added to the discussion below: > http://forum.world.st/f-x-y-or-Table-tp4889801p4889802.html> To start a new topic under Squeak - Beginners, email [hidden email] > To unsubscribe from Squeak - Beginners, click here. > NAML
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## Re: f(x, y) or Table

 In reply to this post by Joseph Alotta Represent your data as objects. If you are thinking of using a dictionary to map key -> value, and you have z := f(x,y) as a function that maps x,y to z, then make x,y be an object, and let that be the key in your dictionary pointing to value z. So define a class that represents x and y. If you have a good data model, you can represent it with objects. If you can not represent it with objects, then you probably can not represent in in a relational database either, so revisit the data model. Note that an index in the database sense is not the same thing as the x,y that you are asking about. if you think in terms of tables in a database, then x and y might be parameters in a select statement and the tables might or might not have indices to make the query run more efficiently. Dave On Wed, Apr 13, 2016 at 08:46:03PM -0500, Joseph Alotta wrote: > Greetings, > > I find a lot of my data needs two indices, f(x,y) instead of one, f(x). > > f(x) would be implemented easily with a Dictionary, > > but how do you implement f(x,y)? > > > I guess this is another way of asking is there a Table object or a Tuple object, > > of even a graphics object Screen that has x,y coordinates with a value? > > > Sincerely, > > Joe. > > > > > > > _______________________________________________ > Beginners mailing list > [hidden email] > http://lists.squeakfoundation.org/mailman/listinfo/beginners_______________________________________________ Beginners mailing list [hidden email] http://lists.squeakfoundation.org/mailman/listinfo/beginners
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## RE: f(x, y) or Table

 In reply to this post by Joseph Alotta Hi Joseph, | aPoint aDictionary | aPoint := Point x: 1 y: 2. aDictionary := Dictionary new. aDictionary at: aPoint put: 'Success!'. ^aDictionary at: aPoint Everything in Smalltalk is an object.  You can use a number or string as your dictionary key but you can also use more complex objects like a Point. The object matching is implemented in #=.  If the objects match then the value will be returned.   All the best, Ron Teitelbaum > -----Original Message----- > From: [hidden email] [mailto:beginners- > [hidden email]] On Behalf Of Joseph Alotta > Sent: Wednesday, April 13, 2016 9:46 PM > To: [hidden email] > Subject: [Newbies] f(x, y) or Table > > Greetings, > > I find a lot of my data needs two indices, f(x,y) instead of one, f(x). > > f(x) would be implemented easily with a Dictionary, > > but how do you implement f(x,y)? > > > I guess this is another way of asking is there a Table object or a Tuple object, > > of even a graphics object Screen that has x,y coordinates with a value? > > > Sincerely, > > Joe. > > > > > > > _______________________________________________ > Beginners mailing list > [hidden email] > http://lists.squeakfoundation.org/mailman/listinfo/beginners_______________________________________________ Beginners mailing list [hidden email] http://lists.squeakfoundation.org/mailman/listinfo/beginners