collections

问题 Issue: I have the following code: foreach(var ItemA in GenericListInstanceB) { ItemA.MethodThatCouldRemoveAnyItemInGenericListInstanceB(); } Obviously i get an error. What i want to do is change GenericListInstanceB to a class i create, that keeps track of items it should remove. Then, when the loop is finished, it removes them all. Same with adding items. This is fine, i can create a class that has an internal list, and a list of items to add and items to remove. Then another method called

问题 I know that failfast iterators check for ConcurrentModificationException on best-effort basis.Why doesnt the methods such as hasnext or hasPrevious check for ConcurrentModificationException and throw it??? The following code works well for the precise reason that these methods are not checked for CME although it has been structurally modifed public static void main(String[] args) { // TODO Auto-generated method stub List<String> lilong = new ArrayList<String>(); lilong.add("Queen"); for

问题 I know that failfast iterators check for ConcurrentModificationException on best-effort basis.Why doesnt the methods such as hasnext or hasPrevious check for ConcurrentModificationException and throw it??? The following code works well for the precise reason that these methods are not checked for CME although it has been structurally modifed public static void main(String[] args) { // TODO Auto-generated method stub List<String> lilong = new ArrayList<String>(); lilong.add("Queen"); for

问题 Is there a fast/simple way to calculate the frequency distribution of a .Net collection using Linq or otherwise? For example: An arbitrarily long List contains many repetitions. What's a clever way of walking the list and counting/tracking repetitions? 回答1: The easiest way is to use a hashmap and either use the value as the key and increment the value, or pick a bucket size (bucket 1 = 1 - 10, bucket 2 = 11 - 20, etc), and increment each bucket by the value. Then you can go through and

问题 Ok just for knowledge , what significance it would made on Collection implementation classes like hashmap , hashset etc if the object's hashcode method always returns 0 in a demoClass . I know it has something to do with putForNullKey of hashmap or other classes of Collection implementation, but dont know much in details. I know for null objects the hascode is 0 so it has specfic method for 0 hashcode. @Override public int hashCode() { return 0; } 回答1: It will make HashMap , HashSet and other

问题 Ok just for knowledge , what significance it would made on Collection implementation classes like hashmap , hashset etc if the object's hashcode method always returns 0 in a demoClass . I know it has something to do with putForNullKey of hashmap or other classes of Collection implementation, but dont know much in details. I know for null objects the hascode is 0 so it has specfic method for 0 hashcode. @Override public int hashCode() { return 0; } 回答1: It will make HashMap , HashSet and other

问题 I'm looking for a semi-general purpose data structure in C# to store arrays of different integer and float types. In some cases, the integers are bit fields where each bit is equally important and loss of precision isn't tolerable. I'm finding this difficult and messy because of the C# type system and my lack of C# fluency. The project: Ethercat periodic packets arrive and are converted to a structure (Packet) and accumulated as Packet[] over the course of an experiment. Each field of Packet

问题 First let me explain why I'm using a KeyedCollection. I'm building a DLL and I have a list of items that I need to add to a collection and have them stay in the order I placed them but I also need to access them by both their index and by key (the key is a property of an object which I already defined). If there is any other simpler collection that does this, then please let me know. Ok now, I need to be able to add items to this collection internally in the DLL but I need it to be publicly

问题 How can the index be out of bounds when it actually is in bounds as shown by the stacktrace? Although the context may not matter we are working on a Lua parser/VM for an IDE on the Netbeans platform and this keeps creeping up. How can this be? Some strange concurrency issue? Thanks in advance for any insights. java.lang.IndexOutOfBoundsException: Index: 14, Size: 16 at java.util.ArrayList.rangeCheck(ArrayList.java:604) at java.util.ArrayList.get(ArrayList.java:382) at org.netbeans.lib.lexer

问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 4 years ago . I recently came across the use case to create a collection that does not accept null values. Guava Constraints seemed to fit the bill. Unfortunately it has been deprecated in Guava Release 15. The class is still available in Release 18, but the access modifier has been set to package private. There are no clues