如何计算一个单词在文本文件中出现的次数

Question

I have been asked to write a program that checks if the team name is present in the text file I had created on my computer and also say how many times it has been repeated on the file? Can you please help me out? I have written the code to check if the word is present but did not know how to check the number of times it is present.

import java.util.*;
import java.io.*;
public class worldSeries 
{
    public boolean checkSeries () throws IOException
    {

        Scanner keyboard = new Scanner(System.in);

        boolean result = false;

        String[] winners = new String[200];

        int  i = 0 ;
        File file = new File ("WorldSeriesWinners.txt");
        Scanner inputFile = new Scanner(file);
        while ( inputFile.hasNext () && i < winners.length )
        {
            winners[i] = inputFile.nextLine(); 
            i++;
        }
        inputFile.close();

        System.out.println(" Enter the Team's name you want to check : " );

        String teamName = keyboard.nextLine();

        for ( int  index = 0 ; index < winners.length ; index ++ )
        {
            if ( teamName.equals(winners[index]))
            {
                result = true;
            }


        }
        return result;
    }

    public static void main(String[]Args)
    {
        worldSeries object1 = new worldSeries();

        try
        {
            System.out.println(" The search result for the Team's name is : " + object1.checkSeries ());
        }
        catch (IOException ioe)
        {
            System.out.println(" Exception!!! ");

            ioe.printStackTrace();
        }

    }
}

Answer 1

Basically you can reuse your already existing for loop

for(int  index = 0 ; index < winners.length ; index++){
        if ( teamName.equals(winners[index])){
            result = true;
        }
}

Introduce a variable counter that is initialized as 0 and incremented if the team name matches.

Additionally I suggest to re-structure your code.

1. Read the content of the file in separate method. Let the method return a String[] that is stored to String[] winners .
2. Ask the user for the team name.
3. Check whether the array winners contains the team name. This happens already in your method checkSeries() . As you can imagine from my previous comments, I would move the Scanner code to the method described in 1. Remember that a methods name should describe what's happening in the method - so checkSeries() should only check and return a yes or no.
4. Reuse the for-loop of checkSeries() in a new method that counts. This method needs only to be called if checkSeries() returned true.

Answer 2

Instead of result = true; you could just increment a counter inside your loop.

For example:

    int counter = 0;
    for ( int  index = 0 ; index < winners.length ; index ++ )
    {
        if ( teamName.equals(winners[index]))
        {
            counter = counter + 1;
        }
    }

And you could then change the return type of your method to int and return counter .

A method that just returns true / false could use the new method. If the returned value is 0, it returns false, else true.

Answer 3

You could use a HashMap with "key" as the word and "value" as the number of occurrences. Whenever you read a word check whether the word is available in the map and increment its value. Let know if you need a code example.

Answer 4

If I were you, I would read all the text input once in a string then split it with the in between white spaces using the method string.split(" ");

This will return an Array of string that contain all the words in your input. Then perform a loop on the Array and count the result of your team in the input.

If you want further help in writing the code, feel free to ask