It might be a little easier if you wrap this in a macro: #define NULL_TO_NIL(obj) ({ __typeof__ (obj) __obj = (obj); __obj == [NSNull null] ? nil : obj; }) Then you can write things like fight.winnerID = NULL_TO_NIL([dict objectForKey:@”winner”]); Alternatively you can pre-process your dictionary and replace all NSNulls with nil before even trying … Read more
You can use the as? operator, which returns an optional value (nil if the downcast fails) if let latestValue = sensor[“latestValue”] as? String { cell.detailTextLabel.text = latestValue } I tested this example in a swift application let x: AnyObject = NSNull() if let y = x as? String { println(“I should never be printed: \(y)”) … Read more
The NULL value for Objective-C objects (type id) is nil. While NULL is used for C pointers (type void *). (In the end both end up holding the same value (0x0). They differ in type however.) In Objective-C: nil (all lower-case) is a null pointer to an Objective-C object. Nil (capitalized) is a null pointer … Read more
Directly from Apple: The NSNull class defines a singleton object you use to represent null values in situations where nil is prohibited as a value (typically in a collection object such as an array or a dictionary). So in your example, that’s exactly what’s happening, the programmer is choosing to put a null object into … Read more
id object = myArray[0];// similar to [myArray objectAtIndex:0] if(![object isEqual:[NSNull null]]) { //do something if object is not equals to [NSNull null] }
nil is the literal null value for Objective-C objects, corresponding to the abstract type id or any Objective-C type declared via @interface. For instance: NSString *someString = nil; NSURL *someURL = nil; id someObject = nil; if (anotherObject == nil) // do something Nil is the literal null value for Objective-C classes, corresponding to the … Read more
They differ in their types. They’re all zero, but NULL is a void *, nil is an id, and Nil is a Class pointer.