2维数组列表

我听说过使用这样的二维数组：

String[][] strArr; 

但有没有办法用这个清单来做这件事？

也许这样？

 ArrayList<String><String> strList; 

并使用这样的东西来添加到它？

 strList.add("hey", "hey"); 

任何方式做这样的事情？ 任何帮助赞赏。

如果有，因为我现在将string放入两个不同的ArrayList中。

Answer 1

你会用

 List<List<String>> listOfLists = new ArrayList<List<String>>(); 

然后，当你需要添加一个新的“行”，你会添加列表：

 listOfLists.add(new ArrayList<String>()); 

当我想要在GUI中持有对几个Point列表的引用时，我主要使用了这个方法，所以我可以绘制多条曲线。 它运作良好。

例如：

 import java.awt.BasicStroke; import java.awt.Color; import java.awt.Dimension; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.Point; import java.awt.RenderingHints; import java.awt.Stroke; import java.awt.event.MouseAdapter; import java.awt.event.MouseEvent; import java.util.ArrayList; import java.util.List; import javax.swing.*; @SuppressWarnings("serial") public class DrawStuff extends JPanel { private static final int PREF_W = 400; private static final int PREF_H = PREF_W; private static final Color POINTS_COLOR = Color.red; private static final Color CURRENT_POINTS_COLOR = Color.blue; private static final Stroke STROKE = new BasicStroke(4f); private List<List<Point>> pointsList = new ArrayList<List<Point>>(); private List<Point> currentPointList = null; public DrawStuff() { MyMouseAdapter myMouseAdapter = new MyMouseAdapter(); addMouseListener(myMouseAdapter); addMouseMotionListener(myMouseAdapter); } @Override public Dimension getPreferredSize() { return new Dimension(PREF_W, PREF_H); } @Override protected void paintComponent(Graphics g) { super.paintComponent(g); Graphics2D g2 = (Graphics2D) g; g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); g2.setStroke(STROKE); g.setColor(POINTS_COLOR); for (List<Point> pointList : pointsList) { if (pointList.size() > 1) { Point p1 = pointList.get(0); for (int i = 1; i < pointList.size(); i++) { Point p2 = pointList.get(i); int x1 = p1.x; int y1 = p1.y; int x2 = p2.x; int y2 = p2.y; g.drawLine(x1, y1, x2, y2); p1 = p2; } } } g.setColor(CURRENT_POINTS_COLOR); if (currentPointList != null && currentPointList.size() > 1) { Point p1 = currentPointList.get(0); for (int i = 1; i < currentPointList.size(); i++) { Point p2 = currentPointList.get(i); int x1 = p1.x; int y1 = p1.y; int x2 = p2.x; int y2 = p2.y; g.drawLine(x1, y1, x2, y2); p1 = p2; } } } private class MyMouseAdapter extends MouseAdapter { @Override public void mousePressed(MouseEvent mEvt) { currentPointList = new ArrayList<Point>(); currentPointList.add(mEvt.getPoint()); repaint(); } @Override public void mouseDragged(MouseEvent mEvt) { currentPointList.add(mEvt.getPoint()); repaint(); } @Override public void mouseReleased(MouseEvent mEvt) { currentPointList.add(mEvt.getPoint()); pointsList.add(currentPointList); currentPointList = null; repaint(); } } private static void createAndShowGui() { JFrame frame = new JFrame("DrawStuff"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.getContentPane().add(new DrawStuff()); frame.pack(); frame.setLocationRelativeTo(null); frame.setVisible(true); } public static void main(String[] args) { SwingUtilities.invokeLater(new Runnable() { public void run() { createAndShowGui(); } }); } } 

Answer 2

 ArrayList<String[]> outerArr = new ArrayList<String[]>(); String[] myString1= {"hey","hey","hey","hey"}; outerArr .add(myString1); String[] myString2= {"you","you","you","you"}; outerArr .add(myString2); //retrieve using: for(int i=0;i<outerArr.size();i++){ String[] myString= new String[4]; myString=outerArr.get(i); for(int j=0;j<myString.length;j++){ System.out.print(myString[j]); } System.out.print("\n"); } 

Answer 3

二维数组只是一个数组的数组。 列表的模拟仅仅是List的List 。

 ArrayList<ArrayList<String>> myList = new ArrayList<ArrayList<String>>(); 

我承认，这不是一个漂亮的解决scheme，尤其是如果你select三维或三维以上的结构。

Answer 4

如果你的平台matrix支持Java 7，那么你可以像下面一样使用

 List<List<String>> myList = new ArrayList<>(); 

Answer 5

事实上，二维数组是X列表的列表，其中X是从典型数据结构到用户定义数据结构之一。 如下面的快照代码，我逐行添加到数组triangle 。 为了创build每一行，我使用方法add来手动添加元素，或者使用方法asList来从一个数据段创build一个列表。

 package algorithms; import java.util.ArrayList; import java.util.Arrays; import java.util.List; public class RunDemo { /** * @param args */ public static void main(String[] args) { // Get n List<List<Integer>> triangle = new ArrayList<List<Integer>>(); List<Integer> row1 = new ArrayList<Integer>(1); row1.add(2); triangle.add(row1); List<Integer> row2 = new ArrayList<Integer>(2); row2.add(3);row2.add(4); triangle.add(row2); triangle.add(Arrays.asList(6,5,7)); triangle.add(Arrays.asList(4,1,8,3)); System.out.println("Size = "+ triangle.size()); for (int i=0; i<triangle.size();i++) System.out.println(triangle.get(i)); } } 

运行示例，它会生成输出：

 Size = 4 [2] [3, 4] [6, 5, 7] [4, 1, 8, 3] 

Answer 6

我知道这是一个很好的答案，但我相信我可以增加我的2美分。

最简单和最灵活的方法是使用几乎“简单的和旧的Java对象”class2D创build您的数组的每个“行”。

下面的例子有一些解释和可执行的（你可以复制和粘贴它，但记得检查包名）：

 package my2darraylist; import java.util.ArrayList; import java.util.List; import javax.swing.JPanel; public class My2DArrayList { public static void main(String[] args) { // This is your "2D" ArrayList // List<Box> boxes = new ArrayList<>(); // Add your stuff // Box stuff = new Box(); stuff.setAString( "This is my stuff"); stuff.addString("My Stuff 01"); stuff.addInteger( 1 ); boxes.add( stuff ); // Add other stuff // Box otherStuff = new Box(); otherStuff.setAString( "This is my other stuff"); otherStuff.addString("My Other Stuff 01"); otherStuff.addInteger( 1 ); otherStuff.addString("My Other Stuff 02"); otherStuff.addInteger( 2 ); boxes.add( otherStuff ); // List the whole thing for ( Box box : boxes) { System.out.println( box.getAString() ); System.out.println( box.getMyStrings().size() ); System.out.println( box.getMyIntegers().size() ); } } } class Box { // Each attribute is a "Column" in you array // private String aString; private List<String> myStrings = new ArrayList<>() ; private List<Integer> myIntegers = new ArrayList<>(); // Use your imagination... // private JPanel jpanel; public void addString( String s ) { myStrings.add( s ); } public void addInteger( int i ) { myIntegers.add( i ); } // Getters & Setters public String getAString() { return aString; } public void setAString(String aString) { this.aString = aString; } public List<String> getMyStrings() { return myStrings; } public void setMyStrings(List<String> myStrings) { this.myStrings = myStrings; } public List<Integer> getMyIntegers() { return myIntegers; } public void setMyIntegers(List<Integer> myIntegers) { this.myIntegers = myIntegers; } public JPanel getJpanel() { return jpanel; } public void setJpanel(JPanel jpanel) { this.jpanel = jpanel; } } 

更新 – 为了回答@Mohammed Akhtar Zuberi提出的问题，我创build了该程序的简化版本，以便更容易地显示结果。

 import java.util.ArrayList; public class My2DArrayListSimplified { public static void main(String[] args) { ArrayList<Row> rows = new ArrayList<>(); Row row; // Insert the columns for each row // First Name, Last Name, Age row = new Row("John", "Doe", 30); rows.add(row); row = new Row("Jane", "Doe", 29); rows.add(row); row = new Row("Mary", "Doe", 1); rows.add(row); // Show the Array // System.out.println("First\t Last\tAge"); System.out.println("----------------------"); for (Row printRow : rows) { System.out.println( printRow.getFirstName() + "\t " + printRow.getLastName() + "\t" + printRow.getAge()); } } } class Row { // REMEMBER: each attribute is a column // private final String firstName; private final String lastName; private final int age; public Row(String firstName, String lastName, int age) { this.firstName = firstName; this.lastName = lastName; this.age = age; } public String getFirstName() { return firstName; } public String getLastName() { return lastName; } public int getAge() { return age; } } 

上面的代码产生以下结果（我在NetBeans上运行它）：

 run: First Last Age ---------------------- John Doe 30 Jane Doe 29 Mary Doe 1 BUILD SUCCESSFUL (total time: 0 seconds) 

Answer 7

以下是如何使用ArrayList对象制作和打印2Dmultidimensional array。

 import java.util.ArrayList; public class TwoD_ArrayListExample { static public ArrayList<ArrayList<String>> gameBoard = new ArrayList<ArrayList<String>>(); public static void main(String[] args) { insertObjects(); printTable(gameBoard); } public static void insertObjects() { for (int rowNum = 0; rowNum != 8; rowNum++) { ArrayList<String> oneRow = new ArrayList<String>(); gameBoard.add(rowNum, oneRow); for (int columnNum = 0; columnNum != 8; columnNum++) { String description= "Description of Objects: row= "+ rowNum + ", column= "+ columnNum; oneRow.add(columnNum, description); } } } // The printTable method prints the table to the console private static void printTable(ArrayList<ArrayList<String>> table) { for (int row = 0; row != 8; row++) { for (int col = 0; col != 8; col++) { System.out.println("Printing: row= "+ row+ ", column= "+ col); System.out.println(table.get(row).get(col).toString()); } } System.out.println("\n"); } }