java - 将词频添加到哈希表

Question

我正在尝试编写一个程序，从文件中获取单词并将它们放入哈希表中。然后我必须像这样计算单词的频率和输出:单词，出现次数。我知道我的添加方法搞砸了，但我不知道该怎么做。我是 Java 新手。

public class Hash {

private Hashtable<String, Integer> table = new Hashtable<String, Integer>();

public void readFile() {

    File file = new File("file.txt");

    try {

        Scanner sc = new Scanner(file);

        String words;

        while (sc.hasNext()) {
            words = sc.next();
            words = words.toLowerCase();

            if (words.length() >= 2) {
                table.put(words, 1);
                add(words);
            }
        }
        sc.close();

    } catch (FileNotFoundException e) {
        e.printStackTrace();
    }
}

public void add(String words) {

    Set<String> keys = table.keySet();
    for (String count : keys) {
        if (table.containsKey(count)) {
            table.put(count, table.get(count) + 1);
        } else {
            table.put(count, 1);
        }
    }
}

public void show() {

    for (Entry<String, Integer> entry : table.entrySet()) {
        System.out.println(entry.getKey() + "\t" + entry.getValue());
    }
}

public static void main(String args[]) {

    Hash abc = new Hash();

    abc.readFile();

    abc.show();
}
}

这是我的文件.txt

one one
two
three
two

输出:

two , 2
one , 5
three , 3

Answer 1

Set<String> keys = table.keySet();
for (String count : keys) {
    if (table.containsKey(count)) {
        table.put(count, table.get(count) + 1);
    } else {
        table.put(count, 1);
    }
}

现在，您正在递增 map 中已有的键。相反，我不认为你想遍历任何东西，你只想为 words 增加 if 条件，我认为它实际上只代表一个词。

if (table.containsKey(words)) {
   table.put(words, table.get(words) + 1);
} else {
   table.put(words, 1);
}