Creating a 2D array in Objective-C with a variable size is simple and straightforward

I've recently started learning objective-c and I'm facing some challenges with 2D arrays. To help explain my issue, I'll make use of my knowledge in javascript.

var row = 10;
var col = 10;
var array[row][col];

for (var i = 0; i < row; i++){
    for (var j = 0; j < col; j++){
        //do something here
    }
}

row = 20;
col = 20;

for (var i = 0; i < row; i++){
    for (var j = 0; j < col; j++){
        //do something here
    }
}

I'm looking to implement this logic in objective-c. Any suggestions on how I can achieve this?

javascriptiosobjective-cxcode

Answer №1

Here is a helpful guide:

NSInteger row = 10;
NSInteger col = 10;

// Creating an array with dynamic size.
NSMutableArray* array = [NSMutableArray new];

for (NSInteger i = 0; i < row; i++) {

    // Values must be added before accessing them.

    NSMutableArray* colArray = [NSMutableArray new];
    [array addObject:colArray];

    for (NSInteger j = 0; j < col; j++) {


        [colArray addObject:someObject];

        // Accessing elements in the array:
        id object = array[i][j];

        // Modifying existing values in the array:
        array[i][j] = someObject;

        // Using NSNull to represent null values instead of nil or null:
        array[i][j] = [NSNull null];
    }
}


// Initializing an array with predefined values:

NSArray* anotherArray = @[objectOne, objectTwo, objectThree];

// Creating a 2-dimensional array:

NSArray* twoDimensionalArray = @[
                                 @[rowOneColumnOne, rowOneColumnTwo, rowOneColumnThree],
                                 @[rowTwoColumnOne, rowTwoColumnTwo, rowTwoColumnThree]
                                 ];

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