What is the easiest way to make a tree?

Question

I like doing game development and I've been doing some with Sprite Kit, but I keep getting stuck while trying to make tree structures. Things for data and configurations.

In javascript I would just make objects of objects of objects and do whatever I wanted. So something like:

[{
    location: {x: 2, y:12},
    allowedNodes: [2,5],
    someflag: true
  }, ...
];

Or make objects and reference them everywhere. I know there is a NSMutableDictionary and structs do exist, but ARC won't let you put any references in them.

I also come from a C++ background and I feel I can do anything at all in C++, but I'm having a really tough time with Objective-C.

Igor Matyushkin · Accepted Answer · 2014-03-29T19:23:01.237

1

NSDictionary is the easiest way to build a tree. It's used in a wide range of cases, for example JSON data always get represented with NSDictionary objects. You can put any reference into the dictionary.

Regarding your example of a tree, it could be represented on Objective-C this way:

@[
    @{
        @"location": @{
            @"x": @2,
            @"y": 12
        },
        @"allowedNodes": @[
            @2,
            @5
        ],
        @"someflag": @YES
    }
];

edited Mar 29 '14 at 19:23

answered Mar 29 '14 at 19:17

Igor Matyushkin

778
4
4

Wow, considering the vagueness and angst in my question I'm surprised I got such a clear answer. The only thing I would add is how to access the values. Doing a search it sorta looked like you could do mydict[@0][@"location"][@"x"], but it does say it needs to be an objects, so @0 might not work. – Sophie McCarrell Mar 29 '14 at 20:54
`NSNumber *x = array[0][@"location"][@"x"];` – Igor Matyushkin Mar 30 '14 at 05:05

score 1 · Answer 2 · edited May 23 '17 at 10:26

1

You're probably looking for the Objective-C 2.0 literals:

@{
    @"Key 1": @[@"Value 1", @"Value 2"],
    @"Key 2": @3,
    @"Key 3": @{@"Nested Key": @"Nested Value"}
}

These let you quickly create NSArray, NSDictionary, and NSNumber.

edited May 23 '17 at 10:26

Community

1
1

answered Mar 29 '14 at 19:22

smileyborg

30,197
11
60
73

score 0 · Answer 3 · answered Mar 29 '14 at 19:13

0

Try using CFTree in Core Foundation:

https://developer.apple.com/library/mac/documentation/corefoundation/Reference/CFTreeRef/Reference/reference.html

answered Mar 29 '14 at 19:13

Rich Tolley

3,812
1
30
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What is the easiest way to make a tree?

3 Answers3