RE: Newbie: basic array questions
RE: Newbie: basic array questions
- Subject: RE: Newbie: basic array questions
- From: "Jonathan E. Jackel" <email@hidden>
- Date: Mon, 28 Apr 2003 15:31:13 -0400
>
1. I have a set of points, each with an ID, x-coord, y-coord, and a time
>
point. How can I set up a mutable array of this type and access each item
>
and any of their 4 attributes?
You could subclass NSObject and establish ID, x-coord, y-coord, and time as
instance variables for your "points". Then you can add instances of your
points to the array. Note that there is a struct (not a class) called
NSPoint for holding x-y coords. So you could have three ivars: ID (an
NSString?), coordinates (NSPoint), and time (NSDate).
Another option is to have each point represented by a dictionary. The keys
would be the names of your "instance variables." Then you can add each
dictionary to an array. You'll have to convert the coordinates to NSNumber
or NSValue.
>
2. I have a 2-dimensional grid of cells, each with a relative
>
location on a
>
grid and an idividual value. In C this was implemented as a
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two-dimensional
>
array (cell [x] [y]) with the value being stored at that x-y location. How
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can I set up a 2-D array in Obj-C?
Objective-C is a superset of C. All your C tricks work. Just remember that
objects are pointers.
>
>
In each case, how would I implement this in Obj-C? What is the most
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efficient way of accessing them if there are anywhere from 1 to
>
15,000 items
>
in each?
Depends. That's not a stupendously large array, so I would not spend a
whole lot of time trying to optimize at this stage. Just test some things
out and see if they work.
Jonathan
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