用Java计算文本文件中的单词

Question

我正在编写一个程序，它将扫描一个文本文件，并计算其中的单词数。 分配的单词的定义是：'单词是仅由字母 (a,...,z,A,...,Z) 组成的非空字符串，由空格、标点符号、连字符包围，行开始，或行结束。 '。

我是java编程的新手，到目前为止我已经设法编写了这个instancemethod，它大概应该可以工作。 但事实并非如此。

public int wordCount() {
    int countWord = 0;
    String line = "";
    try {
        File file = new File("testtext01.txt");
        Scanner input = new Scanner(file);

        while (input.hasNext()) {
            line = line + input.next()+" ";
            input.next();
        }
        input.close();
        String[] tokens = line.split("[^a-zA-Z]+");
        for (int i=0; i<tokens.length; i++){
            countWord++;
        }
        return countWord;

    } catch (Exception ex) {
        ex.printStackTrace();
    }
    return -1;
}

Answer 1

引用文本文件中的单词计数？

    int wordCount = 0;

    while (input.hasNextLine()){

       String nextLine = input.nextLine();
       Scanner word = new Scanner(nextline);

       while(word.hasNext()){
          wordCount++;    
          word.next();
       }
       word.close();
    }
    input.close();

Answer 2

文件中唯一可用的单词分隔符是空格和连字符。 您可以使用regex和split()方法。

int num_words = line.split("[\\s\\-]").length; //stores number of words
System.out.print("Number of words in file is "+num_words);

REGEX（正则表达式）：

\\\\s在空格/换行符和\\\\-在连字符处拆分字符串。 因此，只要有空格、换行符或连字符，句子就会被拆分。 提取的单词被复制到一个数组中并返回，数组的length是文件中的单词数。

Answer 3

you can use java regular expression. 
You can read http://docs.oracle.com/javase/tutorial/essential/regex/groups.html to know about group



    public int wordCount(){

        String patternToMatch = "([a-zA-z]+)";
        int countWord = 0;
        try {
        Pattern pattern =  Pattern.compile(patternToMatch);
        File file = new File("abc.txt");
        Scanner sc = new Scanner(file);
        while(sc.hasNextLine()){
            Matcher matcher = pattern.matcher(sc.nextLine());
             while(matcher.find()){
                 countWord++;
             }
        }
        sc.close();
}catch(Exception e){
          e.printStackTrace();
        }
        return countWord > 0 ? countWord : -1;
    }

Answer 4

void run(String path)
throws Exception
{
    try (BufferedReader reader = new BufferedReader(new InputStreamReader(new FileInputStream(path), "UTF-8")))
    {
        int result = 0;

        while (true)
        {
            String line = reader.readLine();

            if (line == null)
            {
                break;
            }

            result += countWords(line);
        }

        System.out.println("Words in text: " + result);
    }
}

final Pattern pattern = Pattern.compile("[A-Za-z]+");

int countWords(String text)
{
    Matcher matcher = pattern.matcher(text);

    int result = 0;

    while (matcher.find())
    {
        ++result;

        System.out.println("Matcher found [" + matcher.group() + "]");
    }

    System.out.println("Words in line: " + result);

    return result;
}