How can I check if an object in an NSArray is NSNull?

Question

I am getting an array with null value. Please check the structure of my array below:

 (
    \"< null>\"
 )

When I\'m trying to access

Answer 1

A lot of good and interesting answers have been given already and (nealry) all of them work.

Just for completion (and the fun of it):

[NSNull null] is documented to return a singleton. Therefore

if (ob == [NSNull null]) {...} 

works fine too.

However, as this is an exception I don't think that using == for comparing objects is a good idea in general. (If I'd review your code, I'd certainly comment on this).

Answer 2

Awww, guys. This is an easy one.

// if no null values have been returned.
if ([myValue class] == [NSNull class]) {
    myValue = nil;
}

I'm sure there are better answers, but this one works.

Answer 3

In Swift (or bridging from Objective-C), it is possible to have NSNull and nil in an array of optionals. NSArrays can only contain objects and will never have nil, but may have NSNull. A Swift array of Any? types may contain nil, however.

let myArray: [Any?] = [nil, NSNull()] // [nil, {{NSObject}}], or [nil, <null>]

To check against NSNull, use is to check an object's type. This process is the same for Swift arrays and NSArray objects:

for obj in myArray {
    if obj is NSNull {
        // object is of type NSNull
    } else {
        // object is not of type NSNull
    }
}

You can also use an if let or guard to check if your object can be casted to NSNull:

guard let _ = obj as? NSNull else {
    // obj is not NSNull
    continue;
}

or

if let _ = obj as? NSNull {
    // obj is NSNull
}