输出文本文件中最长的单词

Question

I have created a text file writes every word written in the editText box of the android app. I also tried to read the contents of the file using bufferedreader . The problem is, I want to get an output only the longest word in the list created but I can't seem to compare all the strings inputted. My googling only provided info about comparing the length of two strings. How can I compare the length of each line in the text file? Can anyone please guide me on what to do next?

my code looks like this:

 try
   {
        File myFile = new File("/sdcard/logger.file");
        FileInputStream fIn = new FileInputStream(myFile);
        BufferedReader myReader = new BufferedReader(
                new InputStreamReader(fIn));
        String aDataRow = "";
        String aBuffer = "";
        while ((aDataRow = myReader.readLine()) != null)
        {
            aBuffer += aDataRow + "\n";
        }
        show.setText(aBuffer);
        myReader.close();
        Toast.makeText(getBaseContext(),
                "Done reading SD 'mysdfile.txt'",
                Toast.LENGTH_SHORT).show();
        }
   catch (Exception e) 
   {
        Toast.makeText(getBaseContext(), e.getMessage(),
                Toast.LENGTH_SHORT).show();
   }
}

Answer 1

i don't know what your textfile looks like, but if you only have a single word each line, you can use your comparation of two strings. in fact that you already "touch" each word/line while reading it out from the file, why you don't just compare them right there? i modified your code, so that it should do what you want it to do.

try
{
    File myFile = new File("/sdcard/logger.file");
    FileInputStream fIn = new FileInputStream(myFile);
    BufferedReader myReader = new BufferedReader(
            new InputStreamReader(fIn));
    String longestString ="";
    String aDataRow = "";
    String aBuffer = "";
    while ((aDataRow = myReader.readLine()) != null)
    {
        if(longestString.length()<=aDataRow.length()){
            longestString = aDataRow;
        }
        aBuffer += aDataRow + "\n";
    }
    //So here you defenitly got your longestWord in "longestString"
    show.setText(aBuffer);
    myReader.close();
    Toast.makeText(getBaseContext(),
            "Done reading SD 'mysdfile.txt'",
            Toast.LENGTH_SHORT).show();
    }
catch (Exception e) 
{
    Toast.makeText(getBaseContext(), e.getMessage(),
            Toast.LENGTH_SHORT).show();
}

Answer 2

You can use java.util.Scanner,

    try
   {
        File myFile = new File("/sdcard/logger.file");
        Scanner scanner = new Scanner(myFile);
        String bigWord = "";
        while (scanner.hasNextLine()) {
            Scanner wordScanner = new Scanner(scanner.nextLine());
            while (wordScanner.hasNext()) {
                String str = wordScanner.next();
                if(str.length() > bigWord.lenght())
                    bigWord = str;
            }
        }
        show.setText(bigWord);
        Toast.makeText(getBaseContext(),
                "Done reading SD 'mysdfile.txt'",
                Toast.LENGTH_SHORT).show();
   }
   catch (Exception e) 
   {
        Toast.makeText(getBaseContext(), e.getMessage(),
                Toast.LENGTH_SHORT).show();
   }
}

Answer 3

An easy to understand method to solve this problem is to break it into two steps.

The first step is to read all of your separate words into a big array or list. The second step is to go through the array or list, and find the longest word. I'm not sure if you want to get the longest line or the longest word. Maybe they're the same.

Anyway, for your problem specifically, you need to have:

List lines = new ArrayList<>();

Then you need to replace aBuffer += aDataRow + "\\n"; with this: lines.add(aDataRow);

Then when you have finished reading the file, you simply have to have some code like this:

int biggest = 0;
String big_word = "";
for (String row : lines) {
    if (row.length() > biggest) {
        biggest = row.length();
        big_word = row;
    }
}

Toast.makeText(getBaseContext(), "Biggest word is " + big_word, Toast.LENGTH_SHORT).show();

People will recognise that you can combine the creation of the list and the reading of the file, but this method is easier to understand.

Answer 4

Guava solution:

    String longestWord = Files.readLines(new File("/sdcard/logger.file"), Charsets.UTF_8, 
        new LineProcessor<String>() {

            TreeSet<String> set = new TreeSet(new Comparator<String>() {
                @Override public int compare(String o1, String o2) {
                    return o1.length() - o2.length();
                }
            });

         @Override public boolean processLine(String line) {
             set.addAll(Sets.newHashSet(Splitter.on(" ").split(line)));
             return true;
         }

         @Override public String getResult() {
            return set.last();
         }
    });