How to count length of words in a File? Java

Question

I am trying to write a code which would count the number of words of a certain length in a file.

For example:

How are you?

would print:

Proportion of 3-letter words: 100%  (3 words)

I want to count words of length 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13+

Can you please guide me?

I am NOT trying to find the number of words. I am already able to do with this code:

public static int WordCount() throws FileNotFoundException
{
    File file = new File("sample.txt");
    Scanner keyboard = new Scanner(new FileInputStream(file));
    int count=0;
    while(keyboard.hasNext())
    {
      keyboard.next();
      count++;
    }
    return count;
}

I want to find words of a certain length.

UPDATE

I have written the following code:

public static int WordLengthCount() throws FileNotFoundException
{
  File file = new File("hello.txt");
  Scanner keyboard = new Scanner(new FileInputStream(file));
  int count5 = 0;
  int hell = 0; //This is just for the else command to compile

  while(keyboard.hasNext())
  {
    if ( keyboard.next().length() == 5 )
    {
      count5++;
      keyboard.next();
      return count5;
    }
  } return hell;
}

Answer 1

You can use the length() method to count the number of characters in a string (word). From there on, it's just a matter of saving it somewhere. E.g., in Map:

public static Map<Integer, Integer> lengthCounts() throws FileNotFoundException
    Map<Integer, Integer> countMap = new HashMap<>();
    while(keyboard.hasNext())
    {
        String word = keyboard.next();
        int length = word.length();
        Integer currCount = countMap.get(length);
        if (currCount == null) {
            countMap.put (length, 1);
        else {
            countMap.put (length, currCount + 1);
        }
    }
    return countMap;
}

Now you could check the number of words with any particular length, or even print all of them.

EDIT:
If the only thing you need is the percentage of words of a certain length, all you need are two counters - one for the words of that length, and one for all the words:

public static double lengthPercentage(int requiredLength) throws FileNotFoundException
    int allWords = 0;
    int requiredWords = 0;
    while(keyboard.hasNext())
    {
        String word = keyboard.next();
        int length = word.length();
        if (length == requiredLength) {
            ++requiredWords;
        }
        ++allWords;
    }
    // implicit assumption: there's at least on word in the file
    return ((double) requiredWords) / allWords;
}

Answer 2

For example, I have text file named TextFile.txt at C:\ has content:

Ut porttitor libero sodales quam sagittis, id facilisis lectus semper.

and Java code:

import java.io.BufferedInputStream;
import java.io.DataInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;

public class Example {

    public static void main(String[] args) throws IOException {
        File file = new File("C:\\TextFile.txt");
        FileInputStream fis = new FileInputStream(file);
        BufferedInputStream bis = new BufferedInputStream(fis);
        DataInputStream dis = new DataInputStream(bis);    

        if (dis.available() != 0) {
            // Get the line.
            String s = dis.readLine();
            // Put words to array.
            String[] sParts = s.split(" ");
            // Initialize word longest length.
            int longestLength = 1;
            for (String strx : sParts) { // Go through each sPart, the next one is called strx
                // If the document has word longer than.
                if (longestLength < strx.length())
                    // Set new value for longest length.
                    longestLength = strx.length();
            }
            // Because array index from "0".
            int[] counts = new int[longestLength + 1];
            for (String str : sParts) {
                // Add one to the number of words that length has
                counts[str.length()] += 1;
            }
            // We use this type of loop since we need the length.
            for (int i = 1; i < counts.length; i++) {
                System.out.println(i + " letter words: " + counts[i]);
            }
        }
    }
}

// Result:
//        1 letter words: 0
//        2 letter words: 2
//        3 letter words: 0
//        4 letter words: 1
//        5 letter words: 0
//        6 letter words: 2
//        7 letter words: 2
//        8 letter words: 0
//        9 letter words: 3

Answer 3

The other answers are great, but if you are trying to find words of a specific length in a file and you don't like the answers above, then you could also try REGEX. You can test each word and then do what you want with it. If you are looking for a count of words in a file of each length, I think the answer above is better, but if you're looking to detect a word of a specific length you could use .length() or the regex below. Using a strings .lenght() function in my opinion is better, but I'm just giving you an alternative answer and example.

I'll put a small example below.

public class Words{
    public static void main(String [] args){
        String [] words = {"Pizzaaa", "Pizza", "Party"};
        int fives = 0;
        for( String s : words){
            if(s.matches(".{5}")){
                5++;

            }
        }
       System.out.println(fives);
    }
}

Or a better version:

public class Words{
    public static void main(String [] args){
        String [] words = {"Pizzaaa", "Pizza", "Party"};
        int fives = 0;
        for( String s : words){
            if(s.length() == 5){
                5++;

            }
        }
       System.out.println(fives);
    }
}

Edited Below: To demonstrate how it can be used in a file based loop

// other code needed
while(in.hasNext())
{
  String s = in.next();
  if(s.length() == 5)
      fives++;
}

Answer 4

File file = new File("sample.txt");
    Scanner keyboard = new Scanner(new FileInputStream(file));
    int count=0;
    while(keyboard.hasNext())
    {
      keyboard.next();
      // Use a hash map
      // Check the string length and add it to the hash map by checking it already exists. If already exists then get the actual value from hashmap and increment it by one and save it again to the map.

      count++;
    }

So that your final output will be of map with one letter string count, two letter string count etc..