CODEWITHSUNDEEP
iphoneobjective-cioscocoa
GWed
GWed

Reputation: 15653

Accessing array/set of objects with keys

I want to be able to add objects to an NSArray and access them with Keys. Currently the way im doing it is creating a seperate NSDictionary of key-value pairs where the value is an integer number representing the index in my NSArray. This seems like an extra step to me.

If my understanding of NSDictionary is correct, only 'values' can be stored: a pointer to an object cannot.

Surely there must be an equivalent NSDictionary type function that allows objects to be stored and accessed with a key? I have looked through the documentation, but cant seem to find any answers, unless im missing something obvious.

Upvotes: 0

Views: 874

Answers (6)

Applicasa iOS developer
Applicasa iOS developer

Reputation: 256

I think I understand your problem. My suggestion for you is to use NSMutableArray and macros, like:

NSMutableArray *array=[[NSMutableArray alloc]init];
#define SOME_MACRO 0
    id someObject;
    [array insertObject:someObject atIndex:SOME_MACRO];
    id getterObject=[array objectAtIndex:SOME_MACRO];

Of course define the macros in the header file.

Upvotes: 0

user971401
user971401

Reputation:

In short, no.

An array (NSArray) is an ordered collection of references to objects, so simply said, an ordered collection of objects.
As opposed to dictionaries, which are unordered and values are accessed by keys.

You understanding of collections is probably wrong, you don't store values, but pointers (references).

The extra step is necessary if you need to store the references in an array, but in this case, you should consider using a dictionary. An option is to use keys that take care of the order.
For example : 

[myDictionary objectForKey:@"1"];

could be an equivalent of : 

[myArray objectAtIndex:1];

Upvotes: 1

dresende
dresende

Reputation: 2230

I have no experience in Cocoa but looking at the documentation it seems like NSDictionary (or at least NSMutableDictionary) should handle your request (without you using NSArray).

Upvotes: 0

DShah
DShah

Reputation: 9866

You can store objects in NSDictionary and can be accessed via keys...

Upvotes: 1

Vignesh
Vignesh

Reputation: 10251

NSDictionary is to store key value pairs. if you are adding key value pair after you created the dictioanry, use NSMutableDictionary class . example,

[dictionaryObject setObject:@"" forKey:@"abc"];

Upvotes: 1

wattson12
wattson12

Reputation: 11174

Thats wrong, you can store objects in a NSDictionary. Look at the method dictionaryWithObjects:forKeys: or dictionaryWithObjectsAndKeys:

Upvotes: 0

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