arraylist

问题 I am trying to write a procedure do the deep copy of List<List<Integer>> , and I am doing like this: public static List<List<Integer>> clone(final List<List<Integer>> src) { List<List<Integer>> dest = new ArrayList<List<Integer>>(); for( List<Integer> sublist : src) { List<Integer> temp = new ArrayList<Integer>(); for(Integer val: sublist) { temp.add(val); } dest.add(temp); } return dest ; } Is this a good way to do? Is it possible to get rid of the inner loop? The fact is that each of the

问题 What is an array and what is an ArrayList ? What is the difference between them? 回答1: An Array is a high performance way of storing a group of data with the same type because each element is laid out next to it's neighbor in memory. This allows for very fast access because (a) the code can do a little math and jump quickly to any location in the array, and (b) the elements are all grouped together so they tend to be in memory at the same time (fewer page faults and cache misses). An array in

问题 What is an array and what is an ArrayList ? What is the difference between them? 回答1: An Array is a high performance way of storing a group of data with the same type because each element is laid out next to it's neighbor in memory. This allows for very fast access because (a) the code can do a little math and jump quickly to any location in the array, and (b) the elements are all grouped together so they tend to be in memory at the same time (fewer page faults and cache misses). An array in

问题 My goal is to get query a collection and get the documents each document has three or five hashmap in it .my aim is to get the documents with different id's and populate in nested recycler view . But i facing trouble in converting the map values into arraylist My Main Model class: public class BattleGroupPosts { private String userId; public ArrayList<PostBattle> userPost; public BattleGroupPosts() { } ///below there getters and setters and constructions are there My PostBattle Modelclass:

问题 A stable sort is a sort that maintains the relative ordering of elements with the same value. The docs on ArrayList.Sort say that when an IComparer is provided the sort is stable: If comparer is set to null, this method performs a comparison sort (also called an unstable sort); that is, if two elements are equal, their order might not be preserved. In contrast, a stable sort preserves the order of elements that are equal. To perform a stable sort, you must implement a custom IComparer

问题 There are countless examples out there for my problem, I know, but I went through a lot of them and can't figure out where my mistake is. I am iterating over an ArrayList(TestSzenario). The class TestSzenario contains a String Variable called name with proper getters and setters. Here's my code: <td><select name="selectSzenario" id="selectSzenario" size="1"> <c:forEach items="<%=testszenario.getSzenariosForSummary() %>" var="szenario"> <option>${szenario.name}</option> </c:forEach></select><

问题 I am running into an issue with adding a ArrayList into a JComboBox. Can someone give some advice on how to proceed? I can't seem to get the ArrayList to go into the ComboBox. What are the different ways to work with populating JCombobox's with arrayLists? HotelSystem.Java package hotelManage; import java.awt.*; import java.awt.event.*; import java.util.ArrayList; import javax.swing.*; public class HotelSystem extends JFrame implements ActionListener { /** * */ private static final long

问题 I have 2 Arrays. Say, array1 = [1,2,3,4,5] and array2 = [2,3] . How could I check in swift if array1 contains at least one item from array2 ? 回答1: You can do this by simply passing in your array2 's contains function into your array1 's contains function (or vice versa), as your elements are Equatable . let array1 = [2, 3, 4, 5] let array2 = [20, 15, 2, 7] // this is just shorthand for array1.contains(where: { array2.contains($0) }) if array1.contains(where: array2.contains) { print("Array 1

问题 My requirement is the end-user must be able to upload files into the application from internal or external storage and finally display the name of the file in the page. Actual result: Now I've fetched the file name from the storage and displayed the name in my page. Expected Result: The end user must be able to load image or video files from external or internal storage to the application and finally display their name in the page. But don't have any idea about how to load read the file from

问题 My requirement is the end-user must be able to upload files into the application from internal or external storage and finally display the name of the file in the page. Actual result: Now I've fetched the file name from the storage and displayed the name in my page. Expected Result: The end user must be able to load image or video files from external or internal storage to the application and finally display their name in the page. But don't have any idea about how to load read the file from