[Newbies] Re: indexing into a collection

[Joseph Alotta]

Ben, Ron, I made a small example, and it works as you said it would:

a := #( #(1 2)  #(3 4)).
b := a asOrderedCollection.
b  => an OrderedCollection(#(1 2) #(3 4))
c := b select: [ :i | (i first) = 3 ].
c => an OrderedCollection(#(3 4))
d := c first
d =>  #(3 4)
d at: 2 put: 5
d =>  #(3 5)
b  => an OrderedCollection(#(1 2) #(3 5))

Okay, I will check my other code.

Sincerely,

Joe.




> On Jul 26, 2016, at 6:25 PM, Ben Coman [via Smalltalk] <ml-node+s1294792n4908113h52 at n4.nabble.com> wrote:
> 
> Hi Joe, 
> 
> As Ron said, you should not be getting a copy.  If you still have a 
> problem, perhaps best if you post code for a complete example: 
> * class definition (with just two instance variables) 
> * instance variable accessor methods 
> * instance creation & adding to collection 
> * select statement 
> * updating object 
> 
> cheers -ben 
> 
> On Wed, Jul 27, 2016 at 5:53 AM, Ron Teitelbaum <[hidden email]> wrote:
> 
> > Hi Joe, 
> > 
> > If the orderedCollection contains your object DrivingDays then select should give you the object and not a copy. 
> > 
> > You don't need to add it back to the collection just update the object. 
> > 
> > Check your code for anything that might be making a copy. 
> > 
> > All the best, 
> > 
> > Ron Teitelbaum 
> > 
> > 
> > -----Original Message----- 
> > From: [hidden email] [mailto:[hidden email]] On Behalf Of Joseph Alotta 
> > Sent: Tuesday, July 26, 2016 3:04 PM 
> > To: [hidden email] 
> > Subject: [Newbies] indexing into a collection 
> > 
> > Greetings, 
> > 
> > I have a OrderedCollection of DrivingDays. 
> > 
> > 
> > an OrderedCollection(2016-01-02| quigley s| nil|18§ 
> >                      2016-01-03| marianos fresh| nil|5§ 
> >                      2016-01-04| fresh thyme| nil|5§ 
> >                      2016-01-05| panda express| nil|3§ 
> >                      2016-01-06| peets| nil|7§ 
> >                      2016-01-07| starbucks| nil|3§) 
> > 
> > I want to select aDrivingDay object from the list by date, update it by adding mileage and places visited and put it back into the list. 
> > 
> > If I #select the OrderedCollection, I get a copy of the item, not the same one in the OrderedCollection. 
> > 
> > How do I select an item in the list for update? 
> > 
> > Sincerely, 
> > 
> > Joe.
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