Use NSMutableSet: NSMutableSet *intersection = [NSMutableSet setWithArray:array1]; [intersection intersectSet:[NSSet setWithArray:array2]]; [intersection intersectSet:[NSSet setWithArray:array3]]; NSArray *array4 = [intersection allObjects]; The only issue with this is that you lose ordering of elements, but I think (in this case) that that’s OK. As has been pointed out in the comments (thanks, Q80!), iOS 5 and OS X 10.7 … Read more
Use swap: var cellOrder = [1,2,3,4] swap(&cellOrder[0], &cellOrder[1]) Alternately, you can just assign it as a tuple: (cellOrder[0], cellOrder[1]) = (cellOrder[1], cellOrder[0])
Hm, try to look at the NSValue at https://developer.apple.com/documentation/foundation/nsvalue You can use it like struct aStruct { int a; int b; }; typedef struct aStruct aStruct; Then sort of “wrap” it to an NSValue object like: aStruct struct; struct.a = 0; struct.b = 0; NSValue *anObj = [NSValue value:&struct withObjCType:@encode(aStruct)]; NSArray *array = @[anObj]; To … Read more
There is the following Apple’s working example, using sortedArrayUsingSelector: and localizedCaseInsensitiveCompare: in the Collections Documentation: sortedArray = [anArray sortedArrayUsingSelector: @selector(localizedCaseInsensitiveCompare:)]; Note that this will return a new sorted array. If you want to sort your NSMutableArray in place, then use sortUsingSelector: instead, like so: [mutableArray sortUsingSelector:@selector(localizedCaseInsensitiveCompare:)];
themutablearray=[[[themutablearray reverseObjectEnumerator] allObjects] mutableCopy];
copy and mutableCopy are defined in different protocols (NSCopying and NSMutableCopying, respectively), and NSArray conforms to both. mutableCopy is defined for NSArray (not just NSMutableArray) and allows you to make a mutable copy of an originally immutable array: // create an immutable array NSArray *arr = [NSArray arrayWithObjects: @”one”, @”two”, @”three”, nil ]; // create … Read more
NSSortDescriptorss make this really simple. With NSMutableArray you can sort the existing array using sortUsingDescriptors: and with immutable arrays you create a new array using sortedArrayUsingDescriptors: //This will sort by stringProperty ascending, then dateProperty ascending [mutable_array sortUsingDescriptors: @[ [NSSortDescriptor sortDescriptorWithKey:@”stringProperty” ascending:YES], [NSSortDescriptor sortDescriptorWithKey:@”dateProperty” ascending:YES] ]];
First, you must allocate and initialize your objects before use, something like: NSMutableArray * sections = [[NSMutableArray alloc] initWithCapacity:10]; For the rows, you need one object for each, not a single NSMutableArray * rows; Second, depending on whether you’re using Xcode 4.4+ (which introduced subscripting, a.k.a section[i] & section[i] = …) you may have to … Read more
There is a very useful method for this in NSArray i.e. containsObject. NSArray *array; array = [NSArray arrayWithObjects: @”Nicola”, @”Margherita”, @”Luciano”, @”Silvia”, nil]; if ([array containsObject: @”Nicola”]) // YES { // Do something }
You can always iterate without an enumerator. Which means a regular for loop, and when you remove an object:- decrement the index variable and continue;. if you are caching the array’s count before entering the for-loop, then make sure you decrement that too when removing an object. Anyway, I do not see why an array … Read more