iOS: Why can't I set nil to NSDictionary value?

user_587736 0
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This might be very basic question but I was wondering why can't I assign nil as NSDictionary value? I have following statement many places in my code. If [q objectForKey:@"text"] is nil then App is crashing. 

NSMutableDictionary *dict = [[NSMutableDictionary alloc] initWithCapacity:2];
[dict setObject:[q objectForKey:@"text"] forKey:@"text"];

I have to check everywhere for the nil before assigning it to dictionary. Is this the only correct way of doing? Am I missing something obvious? 

if([q objectForKey:@"text"] != nil)
    [dict setObject:[q objectForKey:@"text"] forKey:@"text"];
else
    [dict setObject:@"" forKey:@"text"];
nsdictionary null iphone ios
5 Answers

When using this method:

func setObject(_ anObject: Any, forKey aKey: NSCopying)

Parameters (according to Apple doc's):

anObject:

Raises an invalidArgumentException if anObject is nil. If you need to represent a nil value in the dictionary, use NSNull .

aKey

Raises an invalidArgumentException if aKey is nil.

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