Is NSCache thread safe?
One more thing about NSCache is, it is thread safe. We can access it from any thread without worrying about managing threads while accessing NSCache. You can set & get name for cache. NSCache handles caching & evict of objects for you automatically.
Does NSDictionary retain objects?
NSDictionary. A dictionary stores arbitrary key/value pairs of objects. There’s no notion of a generic object copy for CoreFoundation-classes, thus copy wasn’t possible at that time (*). This only applies if you use CFDictionarySetValue() .
What is the difference between NSDictionary and NSMutableDictionary?
Dictionary contains an array,and that array contains dictionary. Main Difference is: NSMutableDictionary is derived from NSDictionary, it has all the methods of NSDictionary. NSMutableDictionary is mutable( can be modified) but NSDictionary is immutable (can not be modified).
Why use NSCache?
You typically use NSCache objects to temporarily store objects with transient data that are expensive to create. Objects that have subcomponents that can be discarded when not being used can adopt the NSDiscardableContent protocol to improve cache eviction behavior.
What is nsmutablearray and what does NSArray do?
NSArray and its subclass NSMutableArray manage ordered collections of objects called arrays. NSArray creates static arrays, and NSMutableArray creates dynamic arrays. You can use arrays when you need an ordered collection of objects.
How does the NSArray class work in Objective C?
For more information about object literals in Objective-C, see Working with Objects in Programming with Objective-C. In Swift, the NSArray class conforms to the ArrayLiteralConvertible protocol, which allows it to be initialized with array literals.
Can a NSDictionary be substituted for a cfdictionaries object?
Because NSDictionary and CFDictionary are “toll-free bridged,” you can substitute a CFDictionary object for a NSDictionary object in your code (with appropriate casting).
Do you have to override primitive instance methods in NSArray?
Any subclass of NSArray must override the primitive instance methods count and object (at:). These methods must operate on the backing store that you provide for the elements of the collection. For this backing store you can use a static array, a standard NSArray object, or some other data type or mechanism.
