collections

问题 Say I have the following class: class A { String name; Double value; } and a list of the above class objects which might have: [{f 2.1}, {c 1.1}, {a 0.3}... and so on] [{n 0.5}, {f 1.9}, {x 0.1}, {a 1.9}, {b 1.1}... and so on] ... and so on all I want is to do the followings: 1. Building power subsets from the internal list items(N.B: skip the single subsets). 2. Push the subset in another List as an object of the above class A like this: a. if f,c is a subset of 1st element then f,c would be

问题 This question already has an answer here : Closed 7 years ago . Possible Duplicate: Symfony2 validation doesn’t work when Entity Relationships/Associations I have a Form PageFormType, that has just one field named "entries" and no data class. public function buildForm(FormBuilderInterface $builder, array $options) { $builder->add('entries', 'collection', array('type' => new EntryFormType() ); } public function setDefaultOptions(OptionsResolverInterface $resolver) { $resolver->setDefaults

问题 This question already has an answer here : Closed 7 years ago . Possible Duplicate: Symfony2 validation doesn’t work when Entity Relationships/Associations I have a Form PageFormType, that has just one field named "entries" and no data class. public function buildForm(FormBuilderInterface $builder, array $options) { $builder->add('entries', 'collection', array('type' => new EntryFormType() ); } public function setDefaultOptions(OptionsResolverInterface $resolver) { $resolver->setDefaults

问题 I have to create a method which has an ArrayList; I need to remove even numbers from this ArrayList. I have written code for that but there is a logical error which I couldn't identify. Here is my code: static void sortList(){ List <Integer> number=new ArrayList <Integer>(); number.add(11); number.add(45); number.add(12); number.add(32); number.add(36); System.out.println("Unsorted List: "+number); for (int i=0;i<number.size();i++){ int even=number.get(i)%2; if (even==0){ System.out.println(

问题 I am executing below code snippet System.out.println(List.of(1, 2).getClass()); System.out.println(List.of(1, 2, 3).getClass()); output of this code is; class java.util.ImmutableCollections$List2 class java.util.ImmutableCollections$ListN I am expecting java.util.ImmutableCollections$List3 as output for the second statement because there is of() method which takes three parameter, Why java creating ImmutableCollections$ListN but not ImmutableCollections$List3 ? Edited: It is Java-9 question.

问题 I tried to write a small program to demonstrate hash collisions in java when only equals is overridden and not hashcode() method. This was to prove the theory that two unequal objects can have the same hashcode. This was for an Interview question where the behaviour was asked. I created 200,000 objects, stored them in an array and then compared them to see which are duplicates. (For this I am using a nested for loop iterating over an array of objects after the object creation phase.) For

问题 I got two lists: val list1:List[Int] = List(5, 2, 6) val list2:List[Any] = List("a", "b", "c", "d", "e", "f", "g", "h", "i", "j","k") such that list1.sum >= list2.size I want a list of lists formed with elements in list2 consecutively with the sizes mentioned in list1. For example: if list1 is List(5,2,4) the result I want is: List(List("a", "b", "c", "d", "e"),List("f", "g"),List("h", "i", "j","k")) if list1 is List(5,4,6) the result I want is: List(List("a", "b", "c", "d", "e"),List("f", "g

问题 I have created a List where I have kept some strings. But when I am doing binary search within this list, it is returning negative values while the item is in the list . So far my knowledge positive value will be returned when item in the list . But for some items it is returning negative and for some items positive. Code: @Test public void hello() { // List<String> arlst = new ArrayList<String>(); List arlst = new ArrayList(); arlst.add("TP"); arlst.add("PROVIDES"); arlst.add("QUALITY");

问题 I have to use a HashSet where a lot of duplicate value may be inserted. But I want to preserve the earlier data inserted in the hash when a later insertion makes the duplicate. To examine this I have write the following code and insert many duplicate value, but it doesn't satisfy me. Please see the code below - import java.util.HashSet; import java.util.Set; public class SetTest { private static Set<Student> studentSet = new HashSet<Student>(); private static Student s1, s2, s3, s4, s5, s6,

问题 I have to use a HashSet where a lot of duplicate value may be inserted. But I want to preserve the earlier data inserted in the hash when a later insertion makes the duplicate. To examine this I have write the following code and insert many duplicate value, but it doesn't satisfy me. Please see the code below - import java.util.HashSet; import java.util.Set; public class SetTest { private static Set<Student> studentSet = new HashSet<Student>(); private static Student s1, s2, s3, s4, s5, s6,