Just use NSArray*keys=[dict allKeys]; In general, if you wonder if a specific class has a specific method, look up Apple’s own documentation. In this case, see NSDictionary class reference. Go through all the methods. You’ll discover many useful methods that way.
Swift 3 and Swift 2: You can use a dictionary of type [String: Int] to build up counts for each of the items in your [String]: let arr = [“FOO”, “FOO”, “BAR”, “FOOBAR”] var counts: [String: Int] = [:] for item in arr { counts[item] = (counts[item] ?? 0) + 1 } print(counts) // “[BAR: … Read more
It should work – as long as the data variable is actually an array containing a dictionary with the key SPORT NSArray *data = [NSArray arrayWithObject:[NSMutableDictionary dictionaryWithObject:@”foo” forKey:@”BAR”]]; NSArray *filtered = [data filteredArrayUsingPredicate:[NSPredicate predicateWithFormat:@”(BAR == %@)”, @”foo”]]; Filtered in this case contains the dictionary. (the %@ does not have to be quoted, this is done … Read more
What about NOT (CategoryID IN %@)?
Since -allObjects returns an array, you can create a mutable version with: NSMutableArray *array = [NSMutableArray arrayWithArray:[set allObjects]]; Or, alternatively, if you want to handle the object ownership: NSMutableArray *array = [[set allObjects] mutableCopy];
As the Apple documentation about deep copies explicitly states: If you only need a one-level-deep copy: NSMutableArray *newArray = [[NSMutableArray alloc] initWithArray:oldArray copyItems:YES]; The above code creates a new array whose members are shallow copies of the members of the old array. Note that if you need to deeply copy an entire nested data structure … Read more
NSArray and NSMutableArray provide methods to filter array contents. NSArray provides filteredArrayUsingPredicate: which returns a new array containing objects in the receiver that match the specified predicate. NSMutableArray adds filterUsingPredicate: which evaluates the receiver’s content against the specified predicate and leaves only objects that match. These methods are illustrated in the following example. NSMutableArray *array … Read more
Swift 4: Since Swift 4, this functionality has been added to the standard library. You can use it like so: Dictionary(grouping: statEvents, by: { $0.name }) [ “dinner”: [ StatEvents(name: “dinner”, date: “01-01-2015”, hours: 1), StatEvents(name: “dinner”, date: “01-01-2015”, hours: 1), StatEvents(name: “dinner”, date: “01-01-2015”, hours: 1) ], “lunch”: [ StatEvents(name: “lunch”, date: “01-01-2015”, hours: … Read more
NSArray *array1 = [NSArray arrayWithObjects:@”1″, @”2″, @”3″, nil]; NSString *joinedString = [array1 componentsJoinedByString:@”,”]; componentsJoinedByString: will join the components in the array by the specified string and return a string representation of the array.
Try: NSString *myString = [NSNumber stringValue];