Array Questions

Discussion in 'iPhone/iPad Programming' started by Jeremy1026, Jul 21, 2008.

  1. macrumors 68000

    Joined:
    Nov 3, 2007
    #1
    I have a bit of a complex problem revolving around arrays.

    I need to do 5 things with an array:
    Create an array
    Fill the array with 5 variables
    Sort the variables from low to high
    Remove duplicates
    Find out if value1 + 1 = value2 + 1 = value3 + 1 = value4 + 1 = value5

    Any help with this would be greatly appreciated.
     
  2. macrumors newbie

    Joined:
    Jul 22, 2008
    #2
    Sorting an Array

    Hi,
    Create an Array use
    NSMutableArray *array = [[NSMutableArray alloc] initWithCapacity:2];

    Let us suppose we have a class called Artist with a property artistName. artistName is also the key when implementing the get and the set methods.

    To learn more about key-value programming go here
    http://developer.apple.com/documentation/Cocoa/Conceptual/KeyValueCoding/KeyValueCoding.html

    Artist *object1 = [[Artist] alloc] init];
    object1.artistName = @"Two";

    Artist *object2 = [[Artist] alloc] init];
    object2.artistName = @"One";

    Add some objects to the array like this
    [array addObject:eek:bject1];
    [array addObject:eek:bject2];

    Now to sort the array we will use NSSortDescriptor class like this
    NSSortDescriptor *nsd = [[NSSortDescriptor alloc] initWithKey:mad:"artistName" ascending:YES];

    Add the Sort Descriptor class in an array
    NSMutableArray *nsdArray = [[NSMutableArray alloc] init];
    [nsdArray addObject:nsd];

    Now you are ready to sort the array using sortUsingDescriptor method, like this
    [array sortUsingDescriptors:nsdArray];

    Your array will be sorted after the above line is executed.

    To remove duplicates you can use removeObjectIdenticalTo or
    filterUsingPredicate. You will need to create an object of NSPredicate but it uses teh same concepts of key-value programming.

    To learn more about iPhone SDK, please visit http://www.iphonesdkarticles.com

    Thanks
    iPhone SDK Articles
     

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