Kind of null variable IOS
debugging, ios, null
Solution
The second output, `<null>`, comes from the `NSNull` singleton. This is a class called `NSNull` that has a class method `+null` that returns the same singleton instance of `NSNull` every time. The primary purpose of this class it to be able to act as a stand-in for `nil` in places where you can't put `nil`, such as in collections. For example, JSON libraries typically return `NSNull` when the JSON includes `null`.
You can test for this simply by asking if it's `==` to `[NSNull null]` (since it's a singleton), or possibly if `[obj isKindOfClass:[NSNull null]]`. You could use `[obj isEqual:[NSNull null]]` if you like. You could even ask if it's `== kCFNull` if you want, since `CFNull` and `NSNull` are toll-free bridged. Whatever style you want is up to you.
Problem
i am actually debugging my iOS Application: i want to test if a variable is null or not: Stupid question huh ! ``` if (var !=nil) { doSomeWork ; } ``` So if the variable var is equal to nil and we want to print this result in the debugger area we will have something like that: 2012-10-12 21:33:01.553 Application's Name [892:13d03] (null) This is cool, but indeed when i try to print the variable content in the debugger area, it has been showing : 2012-10-12 21:33:01.553 Application's Name [892:13d03] < null > Can you tell me guys what is the difference between this two kinds of null, and how can i test if the second one is equal to nil. Thanks in advance