如何在LinkedList中搜索特定单词并返回它在列表中的位置以及出现次数[重复]

Question

我有一个问题，因为我需要搜索我创建的链表并输出指定单词出现的次数以及列表中单词出现的位置。这一切都是在JavaGUI中完成的，其中特定单词的输入是使用文本字段完成的。我在代码中遇到麻烦的特定按钮是“搜索列表”按钮，我已经将代码添加到其中，但我仍然没有得到我需要的结果。

在此方面的任何帮助都将不胜感激！

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.util.LinkedList;
import java.util.TreeMap;

public class Main {

public static void main(String[] args) {
FilledFrame frame = new FilledFrame();

frame.setVisible( true );
frame.setSize(1000, 1000);
frame.setDefaultCloseOperation(frame.EXIT_ON_CLOSE);
frame.setTitle("Word List");
}
}

class  FilledFrame extends JFrame{
JLabel     addWord;
JTextField addW;
JTextArea wordArea;

// Creating linked list
private LinkedList<String> wordList = new LinkedList();

public FilledFrame(){

    //Create JTextArea
    wordArea                = new JTextArea();

    //Create all the buttons, JLabel and the JPanel
    JButton addButton       = new JButton("Add Word");
    JButton specifiedLetter = new JButton("Display Specific Letter");
    JButton searchList      = new JButton("Search List");
    JButton removeLastOcc   = new JButton("Remove Last");
    JButton removeAll       = new JButton("Remove All Word Occurrence's ");
    JButton clearList       = new JButton("Clear List");

    JPanel panel            = new JPanel();

    //Add buttons and label to the window

    panel.add(addButton);
    add(panel, BorderLayout.NORTH);

    panel.add(specifiedLetter);
    add(panel, BorderLayout.NORTH);

    panel.add(searchList);
    add(panel, BorderLayout.NORTH);

    panel.add(removeLastOcc);
    add(panel, BorderLayout.NORTH);

    panel.add(removeAll);
    add(panel, BorderLayout.NORTH);

    panel.add(clearList);
    add(panel, BorderLayout.NORTH);


    //Create all Text Fields and Labels
     addWord          = new JLabel("Enter word");

     addW             = new JTextField(20);

    JPanel panel1     = new JPanel();

    //Add labels and text fields to the window
    panel1.add(addWord);
    add(panel1, BorderLayout.SOUTH);
    panel1.add(addW);
    add(panel1, BorderLayout.SOUTH);


    //Add JTextArea to the center and make sure user cannot type into it
    add(wordArea, BorderLayout.CENTER);
    wordArea.setEditable( false );


    //  Action listeners for each button

    addButton.addActionListener(new ActionListener() {
        @Override
        public void actionPerformed(ActionEvent e) {

            wordList.add((addW.getText()));
            wordArea.setText(" The word " + addW.getText() + " was added to the list ");
            System.out.println(wordList);
        }
    });

    specifiedLetter.addActionListener(new ActionListener() {
        @Override
        public void actionPerformed(ActionEvent e) {


        }
    });

    //The button I am having trouble with

    searchList.addActionListener(new ActionListener() {
        @Override
        public void actionPerformed(ActionEvent e) {
            String showWord = "";
            TreeMap<String, Integer> treeMap = new TreeMap<>();

            if ((addW.getText()).length() < 1){
               for(String word : wordList)
               {
                    treeMap.put(word, 1);
                    treeMap.keySet().contains(word);

                    if (treeMap.containsKey(word)) {
                        treeMap.replace(word, treeMap.get(word)+1);
                    }
                    else{
                        treeMap.put(word, 1);
                    }
               }

                wordArea.setText(showWord);
                for (String word: wordList){
                    System.out.println(" This word appears " + word);
                }

            }

            }


        });

Answer 1

匿名用户

试试这个解决方案：

Map<String, List<Integer>> map = new HashMap<>();
IntStream.range(0, list.size())
         .forEach(i -> {
             map.computeIfAbsent(list.get(i), s -> new ArrayList<>()).add(i);
         });

它将把所有索引存储在列表地图中。现在，您可以通过映射轻松获得索引。通过映射获取（str）或发生次数。获取（str）。size（）。

请注意，此解决方案一次执行所有操作。因此，您不需要迭代任何集合两次。

Answer 2

您可以使用java 8中的Collector将您编写的整个逻辑替换为简单的行：

 Map<String, Long> collect = list.stream()
          .collect(Collectors.groupingBy(Function.identity(), Collectors.counting()));

在这里，您将获得地图

要找到它出现的位置，您可以遍历列表并从刚刚创建的map中找到单词的第一次出现。