number locales looks like numbers but they are character
in type so that ": can be ommitted. I agree with you.
Ср, 04 июн 2014, Devon McCormick написал(а):
> I suppose you could do something like this:
>
> coclass 'Account'
> create =: verb define
> balance =: 0
> fname =: ''
> lname =: ''
> )
> coclass 'base'
> list =. 5 $ < 'Account'
> objs=. conew &> list
> objs
> +-+-+-+-+-+
> |1|2|3|4|5|
> +-+-+-+-+-+
> conames''
> 1 2 3 4 5 Account
> (<''''''),~&.>(<'create_'),&.>(":&.>objs),&.><'_'
> +-----------+-----------+-----------+-----------+-----------+
> |create_1_''|create_2_''|create_3_''|create_4_''|create_5_''|
> +-----------+-----------+-----------+-----------+-----------+
> ".&>(<''''''),~&.>(<'create_'),&.>(":&.>objs),&.><'_'
>
>
>
>
>
> balance_1_
> 0
> (<'balance_'),&.>(":&.>objs),&.><'_'
> +----------+----------+----------+----------+----------+
> |balance_1_|balance_2_|balance_3_|balance_4_|balance_5_|
> +----------+----------+----------+----------+----------+
> ".&>(<'balance_'),&.>(":&.>objs),&.><'_'
> 0 0 0 0 0
>
> But this all seems rather clumsy compared to simply using arrays directly
> rather than this vector of object names, e.g.:
>
> 'bals fnms lnms'=.
> (5$0);('Jon';'Dick';'Harry';'Sally';'May');<'Smith';'Jones';'Black';'White';'Eye'
> bals
> 0 0 0 0 0
> fnms
> +---+----+-----+-----+---+
> |Jon|Dick|Harry|Sally|May|
> +---+----+-----+-----+---+
> lnms
> +-----+-----+-----+-----+---+
> |Smith|Jones|Black|White|Eye|
> +-----+-----+-----+-----+---+
>
> I'd be very interested in a concrete example of how using objects
> simplifies matters.
>
>
>
> On Wed, Jun 4, 2014 at 11:16 AM, Jon Hough <[email protected]> wrote:
>
> > I hope I'm not spamming the forum with my questions.
> > I am still getting my head around OOP in J.
> > My class:
> >
> > coclass 'Account'
> >
> > create =: verb define
> > balance =: 0
> > fname =: ''
> > lname =: ''
> > )
> > It's just a dummy 'Account' class with balance, first name and last name.
> > I want to create several objects in a list:
> >
> > list =. 5 $ < 'Account'
> >
> > list
> >
> >
> > ┌───────┬───────┬───────┬───────┬───────┐│Account│Account│Account│Account│Account│└───────┴───────┴───────┴───────┴───────┘
> >
> > So I have my list of 5 Accounts. Now I want to be able to access their
> > fields, functions by indexing the list.
> > e.g. in Java if I have an array of Accounts
> > Account[] accounts = new Account[5];
> > I can access the fields from the array index:
> > for(int i = 0; i<5; i++){
> > accounts[i].fname = "No name given";
> > }
> > In J,
> > I tried the following:
> > create__(1{list)
> > |value error: create__
> > | create__(1{list)
> > I tried to call the create function of the 2nd Account (index 1) of th
> > elist. It seems I can't append 1{list to create__.
> > Next I thought about making a function to do the work for me:
> > NB. function to return y's fname...
> > func =: verb define acct =. y name =: fname__acct name
> > )
> > The above function assumes y is an instance of Account.
> > Alas, func 1{list doesn't work.
> > However if I do:
> > acct =: 1{list
> > func acct
> > This will return the fname.
> > But I have to explicitly define acct, which is not particularly terse. Is
> > there a way to call functions from the list of objects?
> >
> > ----------------------------------------------------------------------
> > For information about J forums see http://www.jsoftware.com/forums.htm
>
>
>
>
> --
> Devon McCormick, CFA
> ----------------------------------------------------------------------
> For information about J forums see http://www.jsoftware.com/forums.htm
--
regards,
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