how to Check NSString is null or not [duplicate]
There are three possible interpretations of "null" NSString:
someStringPtr == nil(id)someStringPtr == [NSNull null]someStringPtr.length == 0
If you may have the possibility of all 3, the 3rd check subsumes the first, but I don't know of a simple check for all three.
In general, JSON will return [NSNull null] for a null JSON value, but some kits may return @"" (length == 0) instead. nil will never be used in iOS since it can't be placed in arrays/dictionaries.