字数统计功能可对txt文件中的字进行计数

Question

I'm very new to java here so please bear with me.

I'm currently trying to create code that does the following:

1. Add code to your processFile function that counts the number of times each word appears in the file.

2. Add code to your processFile function that loops through your HashMap to find the most frequent word. After your loop, the variable added for bonus requirement #1 should contain the value for the most frequent word.

So far I've come up with this and was wondering if anyone could please help me progress further.

        Map<String, Integer> freq = new Hashmap<String, Integer>();
        FileInputStream fi = new FileInputStream("readwords,txt");
        Scanner input = new Scanner(fi);
        while (input.hasNext()) {
        String word = input.next().toLowerCase();
        Integer f = freq.get(word);
            if (f == null) {
                freq.put(word,1);
            }
            else { 
                freq.put(word,f+1);
            }
        }

Thank you

Answer 1

Your syntax is close, but you've mixed String declaration styles, your generic type is missing a > and your variable names are inconsistent. I think you wanted something like,

Map<String, Integer> map = new HashMap<>();
File file = new File("readwords.txt");  
try (Scanner input = new Scanner(file)) {
    while (input.hasNext()) {
        String word = input.next().toLowerCase();
        Integer f = map.get(word);
        if (f == null) {
            map.put(word, 1);
        } else {
            map.put(word, f + 1);
        }
    }
} catch (FileNotFoundException fnfe) {
    fnfe.printStackTrace();
}

Answer 2

For counting the words and for getting most frequently used word you can try this:

   public void processFile() throws Exception {
        Map<String, Integer> freq = new HashMap<>();
        FileInputStream fi = new FileInputStream("readwords.txt");
        String mostFreqWord = null;
        Integer highestFreq = 0;
        Scanner input = new Scanner(fi);
        while (input.hasNext()) {
            String word = input.next().toLowerCase();
            Integer f = freq.get(word) == null ? 1 : freq.get(word) + 1;

            freq.put(word, f);

            if(f > highestFreq) {
                mostFreqWord = word;  // set most frequent word
                highestFreq = f;      // frequency of most frequent word
            }

        }

        System.out.println("Word :" + mostFreqWord
                + " is the most frequent word with frequency:" + highestFreq);
    }

Since I have modified the code you already posted, here is the explanation of modification that I did (I assume that you already know what your original code was doing).

Inside loop, below line checks if word word has encountered first time in loop, if yes then sets it's frequency as 1 otherwise it increments frequency for that word.

Integer f = freq.get(word) == null ? 1 : freq.get(word) + 1;

Then it sets latest frequency for the word: freq.put(word, f);

Statement if(f > highestFreq) checks if the highest frequency is still highest, if not then updates highestFreq and mostFreqWord words.