How to count occurrence of each character in the alphabet with a file

Question

I would like to know how to go about starting a program that reads in a file and goes line by line counting the occurrence of each letter in the alphabet.I know I would like to use an array that holds the alphabets, but I am not sure how to go about reading each line and then printing the count out for each alphabetical occurrence.

nothing right now, but the code that reads in the file. I'm trying to get an idea where to start — unlimited4311, Nov 28 '14 at 19:51
Well, there are plenty of tutorials about reading files and printing arrays and the question about finding character occurrences in a String gets asked twice a week. I guess there shouldn't be a problem finding and using that stuff. — Tom, Nov 28 '14 at 19:51
[MCVE](http://stackoverflow.com/help/mcve) - If you don't know how to do a certain part, at least provide the parts that you know how to do. — Compass, Nov 28 '14 at 19:52

score 2 · Accepted Answer · edited May 23 '17 at 12:27

2

  BufferedReader reader = new BufferedReader(new FileReader("somefile.txt"));
    int ch;
    char charToSearch='a';
    int counter=0;
    while((ch=reader.read()) != -1) {
        if(charToSearch == (char)ch) {
            counter++;
        }
    };
    reader.close();

    System.out.println(counter);

Reference: Counting letter occurrence

edited May 23 '17 at 12:27

Community

1
1

answered Nov 28 '14 at 19:52

Ismael Di Vita

1,806
1
20
35

Nitesh · Answer 2 · 2014-11-28T20:24:26.367

try this

public void countOccurence() {
 BufferedReader reader
                     = new BufferedReader(new FileReader("somefile.txt"));

String text = "";
while((ch=reader.read()) != -1) {
       text = text +ch;
    };
    reader.close();


 for(Character a :"abcdefghijklmnopqrstuvwxyz0123456789".toCharArray())
    {

         int ch;
         char charToSearch=a;
         int counter=0;
         for(Character b : text.toCharArray())
            {
              if(charToSearch == (char)b) {
                counter++;
                  }
            }

    System.out.pritln("Character: " +charToSearch+ " occurs " + counter 
    + " times.");

         }
    }

Mark as up, if it works for you :)

You're reading the whole file `36` times? Yes, very good idea. — Tom, Nov 28 '14 at 20:15

score 0 · Answer 3 · answered Nov 28 '14 at 20:26

    public void count() throws Exception {
        int[] array = new int[26];
        BufferedReader br = new BufferedReader(new FileReader("file.txt"));
        int ch;
        while((ch = br.read()) != -1) {
            if (ch > 64 && ch < 97) // Upper case letters
                ch += 32; // to get the ascii value of the letter in lowercase
            if(-1 < ch-97 && ch-97 < 26)
                array[ch-97] += 1;
        }
        br.close();
        int i = 0;
        for (char chr = 'a'; chr <= 'z'; chr++) {
            System.out.printf("%s --> %d\n", chr, array[i]);
            i++;
        }
    }

score 0 · Answer 4 · answered Nov 28 '14 at 20:47

BufferedReader reader = new BufferedReader(new FileReader("somefile.txt"));
int ch; 
Map<char, int> charCount = new Map<char, int>();
while((ch=reader.read()) != -1) {
    if(charCount.contains(ch)) {
        charCount.put(ch, charCount.get(ch)++);
    } else {
        charCount.put(ch, 1);
    }
}
reader.close();

for(String key: charCount.keySet())
    System.out.println(key + " - " + charCount.get(key));
System.out.println();

This will keep a counter for EVERY character in the file. If you want to limit this set to an alphabet, this can be done easily by checking is ch is in the alphabet before putting it in charCount.

How to count occurrence of each character in the alphabet with a file

4 Answers4

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