What is fast enumeration?
What is fast enumeration?
Fast enumeration is a language feature that allows you to efficiently and safely enumerate over the contents of a collection using a concise syntax.
What is enumeration Swift?
An enumeration defines a common type for a group of related values and enables you to work with those values in a type-safe way within your code. Enumerations in Swift are much more flexible, and don’t have to provide a value for each case of the enumeration.
What is difference between enum and enumeration in Swift?
An enumeration is a user-defined data type which consists of set of related values. Keyword enum is used to defined enumerated data type.
Can you extend an enum Swift?
We can extend the enum in two orthogonal directions: we can add new methods (or computed properties), or we can add new cases. Adding new methods won’t break existing code. Adding a new case, however, will break any switch statement that doesn’t have a default case.
How is the NSFastEnumeration construct used in a collection?
This construct is used to enumerate objects in a collection which conforms to the NSFastEnumeration protocol. This approach has a speed advantage because it stores pointers to several objects (obtained via a single method call) in a buffer and iterates through them by advancing through the buffer using pointer arithmetic.
Why does NSEnumerator place only one object in the buffer?
The reason is that the default NSEnumerator implementation of -countByEnumeratingWithState:objects:count: places only one object in the buffer on each call. I reported this in radar://6296108 (Fast enumeration of NSEnumerators is sluggish) but it was returned as Not To Be Fixed.
How to use an NSEnumerator in a while loop?
You can also use -enumerateObjectsWithOptions:usingBlock: and pass NSEnumerationConcurrent and/or NSEnumerationReverse as the options argument. The standard idiom for pre-10.5 is to use an NSEnumerator and a while loop, like so: I recommend keeping it simple.
What does NSEnumerator do for autoreleased objects?
Further, an NSEnumerator (at least those provided by Apple code) retains the collection it’s enumerating as long as there are more objects, so you don’t have to worry about how long an autoreleased object will exist.
What is fast enumeration? Fast enumeration is a language feature that allows you to efficiently and safely enumerate over the contents of a collection using a concise syntax. What is enumeration Swift? An enumeration defines a common type for a group of related values and enables you to work with those values in a type-safe…