java - 使用 HashMap 的字数统计程序

Question

import java.io.*;
import java.util.*;

public class ListSetMap2 
{
    public static void main(String[] args)
    {
        Map<String, Integer> my_collection = new HashMap<String, Integer>();
        Scanner keyboard = new Scanner(System.in);

        System.out.println("Enter a file name");
        String filenameString = keyboard.nextLine();
        File filename = new File(filenameString);
        int word_position = 1;
        int word_num = 1;

        try
        {
            Scanner data_store = new Scanner(filename);
            System.out.println("Opening " + filenameString);
            while(data_store.hasNext())
            {
                String word = data_store.next();
                if(word.length() > 5)
                {
                    if(my_collection.containsKey(word))
                    {
                        my_collection.get(my_collection.containsKey(word));
                        Integer p = (Integer) my_collection.get(word_num++);
                        my_collection.put(word, p);
                    }
                    else
                    {
                        Integer i = (Integer) my_collection.get(word_num);
                        my_collection.put(word, i);
                    }
                }
            }
        }
        catch (FileNotFoundException e)
        {
            System.out.println("Nope!");
        }
    }
}

我正在尝试编写一个程序，它输入/扫描一个文件，将单词记录在 HashMap 集合中，然后计算该单词在文档中出现的次数，只计算超过 5 个字符的单词。

中间有点乱，但我遇到了如何计算该词出现的次数以及如何对每个词进行单独计数的问题。我确定这里有一个简单的解决方案，我只是想念它。请帮忙!

Answer 1

你设置词频的逻辑是错误的。这是一个适合您的简单方法:

    // if the word is already present in the hashmap
    if (my_collection.containsKey(word)) {
        // just increment the current frequency of the word
        // this overrides the existing frequency
        my_collection.put(word, my_collection.get(word) + 1);
    } else {
        // since the word is not there just put it with a frequency 1
        my_collection.put(word, 1);
    }