Array is a struct, therefore it is a value type in Swift. NSArray is an immutable Objective C class, therefore it is a reference type in Swift and it is bridged to Array<AnyObject>. NSMutableArray is the mutable subclass of NSArray. var arr : NSMutableArray = [“Pencil”, “Eraser”, “Notebook”] var barr = [“Pencil”, “Eraser”, “Notebook”] func … Read more
var sortedCollection = _.sortBy(collection, function(item){ return firstArray.indexOf(item.guid) });
You are asking specifically about ArrayList and HashMap, but I think to fully understand what is going on you have to understand the Collections framework. So an ArrayList implements the List interface and a HashMap implements the Map interface. So the real question is when do you want to use a List and when do … Read more
I Don’t know what do you mean exactly, but technially speaking, this is not possible without a loop. May be you mean using a LINQ, like for example: list.Where(x=>x.Title == title) It’s worth mentioning that the iteration over is not skipped, but simply wrapped into the LINQ query. Hope this helps. EDIT In other words … Read more
I guess this depends on your use case, but why would you need a CopyOnWriteMap when you already have a ConcurrentHashMap? For a plain lookup table with many readers and only one or few updates it is a good fit. Compared to a copy on write collection: Read concurrency: Equal to a copy on write … Read more
I think the point is that there is no reason for a getFirst(iterable) in that this could be done with iterable.iterator().next(). Guava makes an excellent attempt to keep the API small and so does not add things that could / should be done easily another way. On the other hand, there is not already a … Read more
The sort order is always ascending, where the Comparator defines which items are larger than others. From the documentation for Collections.sort(List<T> list, Comparator<? super T> c): Sorts the specified list according to the order induced by the specified comparator. From the documentation for Comparator.compare(T,T): Compares its two arguments for order. Returns a negative integer, zero, … Read more
You need to create a new KeyValuePair1 – but bear in mind that KVP is a value type (a struct) anyway, so it’s not like you’re introducing a new inefficiency by doing this. Any method returning a KVP would be creating a copy anyway – you’re just creating the instance directly. You could always add … Read more
AllKeys is an O(n) operation, while Keys is O(1). This is because AllKeys copies the keys into a new array, while Keys just returns a reference to NameValueCollection‘s private key collection. So beyond the difference in performance, the collection returned by Keys will change with the base collection as it’s just a reference to the … Read more
I am generally in the camp of just using a List directly, unless for some reason I need to encapsulate the data structure and provide a limited subset of its functionality. This is mainly because if I don’t have a specific need for encapsulation then doing it is just a waste of time. However, with … Read more