How to produce 2 dimensional Array in Objective C

Question

How do i produce a 2 dimensional NSMutable array as this:

Array:

=>[item1]=>[item1a,item1b,item1c...]
=>[item2]=>[item2a,item2b,item2c...]
...
=>[item10]=>[item10a,item10b,item10c...]

So far i've only been successful up to the [item1]=>[item1a,item1b,item1c...]

When i try to add more 2 dimensional array it keeps overriding the first row.

Stay tuned, some of the additions made to clang will allow some shorthand syntax for creating arrays that will make multi-dimensional arrays much easier. Syntax will look like array = @[ @[ item1a, item1b ], @[ item2a, item2b ] ];. This will probably be part of the next release of Xcode. — dreamlax
– dreamlax, Commented May 10, 2012 at 4:36
Just how many times will this question be asked? stackoverflow.com/questions/10485521/… — Richard J. Ross III
– Richard J. Ross III, Commented May 10, 2012 at 4:37
@Richard: The question you linked is not about NSArrays inside of NSArrays. — jscs
– jscs, Commented May 10, 2012 at 18:03
@JacquesCousteau it's about 2 dimensional arrays in objective-c. The answer can be used for objects as well. — Richard J. Ross III
– Richard J. Ross III, Commented May 10, 2012 at 18:35
@RichardJ.RossIII: Except there is no clear ownership of objects. — dreamlax
– dreamlax, Commented May 10, 2012 at 20:21

MByD · Accepted Answer · 2012-05-10 05:54:54Z

5

Create NSMutableArray and assign NSMutableArrays to it as its objects.

For example:

NSMutableArray * myBig2dArray = [[NSMutableArray alloc] init];

// first internal array
NSMutableArray * internalElement = [[[NSMutableArray alloc] init] autorelease];
[internalElement addObject:@"First - First"];
[internalElement addObject:@"First - Second"];
[myBig2dArray addObject:internalElement];

// second internal array
internalElement = [[[NSMutableArray alloc] init] autorelease];
[internalElement addObject:@"Second - First"];
[internalElement addObject:@"Second - Second"];
[myBig2dArray addObject:internalElement];

edited May 10, 2012 at 5:54

answered May 10, 2012 at 4:33

MByD

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Comments

rooster117 · Accepted Answer · 2012-05-10 04:33:49Z

3

To make a 2 dimensional array you would make an array of arrays.

NSArray *2darray = [NSArray arrayWithObjects: [NSArray arrayWithObjects: @"one", @"two", nil], NSArray arrayWithObjects: @"one_2", @"two_2", nil]];

It gets very verbose but that is the way I know how to do this. An array of dictionaries may be better for your situation depending on what you need.

answered May 10, 2012 at 4:33

rooster117

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Comments

atastrophic · Accepted Answer · 2013-04-21 10:23:28Z

0

I wrote an NSMutableArray wrapper for easy use as a Two Dimensional array. It is available on github as CRL2DArray here . https://github.com/tGilani/CRL2DArray

answered Apr 21, 2013 at 10:23

atastrophic

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1 Comment

xaphod Over a year ago

This would be a lot more useful if it provided a way to access the two dimensional array in a 1 dimensional way. Example: array{ {orange, pear} {red, blue, green} {square, circle} } .. array1D[3] = blue

Prasad tj · Accepted Answer · 2014-12-02 10:44:16Z

First you to have set An NSMutableDictionary on .h file

        @interface MSRCommonLogic : NSObject
        {
            NSMutableDictionary *twoDimensionArray;
        }

        then have to use following functions in .m file


        - (void)setValuesToArray :(int)rows cols:(int) col value:(id)value
        {
            if(!twoDimensionArray)
            {
                twoDimensionArray =[[NSMutableDictionary alloc]init];
            }

            NSString *strKey=[NSString stringWithFormat:@"%dVs%d",rows,col];
            [twoDimensionArray setObject:value forKey:strKey];

        }

        - (id)getValueFromArray :(int)rows cols:(int) col
        {
            NSString *strKey=[NSString stringWithFormat:@"%dVs%d",rows,col];
            return  [twoDimensionArray valueForKey:strKey];
        }

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