NSMutableDictionary: mutating method sent to immutable object

Question

The following code is returning an exception with the following error message \"mutating method sent to immutable object\" when attempting to removeObjectForKey

Answer 1

i found same issue and found solution hope it will help some one.

arrayOfferId = defaults.objectForKey("offerId")?.mutableCopy() as! NSMutableArray

NSUserDefaults returns immutable objects, even if you put in mutable ones. You must call -mutableCopy on the returned value to get a mutable collection. so when you get value from NSUserDefault use mutableCopy()