如何用文件计算字母中每个字符的出现

Question

我想知道如何启动一个程序，该程序读取文件并逐行计算字母表中每个字母的出现。我知道我想使用一个保存字母的数组，但我不是确保如何阅读每一行，然后打印出每个字母出现的计数。

Answer 1

  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

Answer 2

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 :)

Answer 3

    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++;
        }
    }

Answer 4

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 .