Use of clone() in Java is tricky and questionable1,2. Effectively, clone() is a copy constructor and for that, the Dart List, Map and Set types each have a named constructor named .from() that perform a shallow copy; e.g. given these declarations Map<String, int> numMoons, moreMoons; numMoons = const <String,int>{ ‘Mars’ : 2, ‘Jupiter’ : 27 … Read more
The Counter class was added to the module in Python 2.7. You are most likely using Python 2.6 or older. From the collections.Counter() documentation: New in version 2.7. On python 2.5 or 2.6, use this backport instead.
IEnumerable<T> represents a series of items that you can iterate over (using foreach, for example), whereas IList<T> is a collection that you can add to or remove from. Typically you’ll want to be able to modify an Order by adding or removing OrderLines to it, so you probably want Order.Lines to be an IList<OrderLine>. Having … Read more
When you write an impl Check and specialize your type Error with a concrete type, you are ending up with different types. In other words, Check<Error = NegativeError> and Check<Error = EvenError> are statically different types. Although you might expect Check<Error> to describe both, note that in Rust NegativeError and EvenError are not sub-types of … Read more
You can use $lookup ( multiple ) to get the records from multiple collections: Example: If you have more collections ( I have 3 collections for demo here, you can have more than 3 ). and I want to get the data from 3 collections in single object: The collection are as: db.doc1.find().pretty(); { “_id” … Read more
Length() tends to refer to contiguous elements – a string has a length for example. Count() tends to refer to the number of elements in a looser collection. Size() tends to refer to the size of the collection, often this can be different from the length in cases like vectors (or strings), there may be … Read more
Apache commons collections 4 has a CircularFifoQueue<> which is what you are looking for. Quoting the javadoc: CircularFifoQueue is a first-in first-out queue with a fixed size that replaces its oldest element if full. import java.util.Queue; import org.apache.commons.collections4.queue.CircularFifoQueue; Queue<Integer> fifo = new CircularFifoQueue<Integer>(2); fifo.add(1); fifo.add(2); fifo.add(3); System.out.println(fifo); // Observe the result: // [2, 3] If … Read more
If you need an empty read-only collection, you can call the emptyList function: var valueContractTransactionsVO: Collection<ValueContractTransactionVO> = emptyList() And if the type of valueContractTransactionsVO being a Collection is not significant for your case, you can specify the type argument of the emptyList function and let the compiler to infer its type to List<ValueContractTransactionVO>: var valueContractTransactionsVO … Read more