Re: NSArray NSDictionary Tree Q.
Re: NSArray NSDictionary Tree Q.
- Subject: Re: NSArray NSDictionary Tree Q.
- From: Ian McGregor <email@hidden>
- Date: Sat, 13 Dec 2003 17:01:36 -0800
Thanks Aaron.
Unfortunately the app has to run on 10.2.x, and as I understand it
(now) the valueForKey is a new 10.3 only thing. Thanks for the
explanation of it though. It actually makes more sense now!
Cheers,
Ian
On 13-Dec-03, at 4:30 PM, Aaron Tuller wrote:
if i understand you correctly, yes, use Key Value Coding, it's already
implemented on NSDictionary.
say you now write something like this:
[[[someDict objectForKey:@"key1"] objectForKey:@"key2"]
objectForKey:@"key3"]
you can do:
[someDict valueForKeyPath:@"key1.key2.key3"];
where the keypath is any NSString, you could store it externally or
generate it at runtime.
and there's also
- (void)takeValue:(id)value forKeyPath:(NSString *)key;
so you could set the value at a certain path.
check out:
http://developer.apple.com/documentation/Cocoa/Conceptual/
KeyValueCoding/index.html
if this isn't what you're asking, sorry for the noise.
-aaron
At 10:01 AM -0800 12/13/03, Ian McGregor wrote:
I have an immutable NSArray containing a tree-like data structure.
NSArray *rootItems
- NSDictionary item
- NSDictionary item
- NSDictionary item
each NSDictionary item contains an NSArray *children, which can
contains even more NSDictionary *item objects.
Basically a tree using NSArray and NSDictionary
My model requires these objects to be stored in an immutable fashion,
but I make a mutable copy when I am altering the data, no dramas or
probs there.
The problem I am having, is finding an easier method the traverse the
"nodes" or NSDictionary *item's to change their values.
For example, if am currently using unique id's for the group nodes,
and
another set of unique id's for the object nodes. I have had some
success using various recursive methods to locate the nodes I wish to
change, but actually changing the node is confusing me.
Any suggestions?
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