如何在每個單詞中找到第一個字母？

Question

我在哪里編輯此代碼以查找輸入文件中每個單詞的第一個字母，保留頻率和百分比，而不是每個字符？ 例如，我在哪里可以實現charAt(0)或我需要更改/添加什么？

import java.util.Scanner;
import java.io.File;
import java.io.FileNotFoundException;

public class FirstWordLetters
{
    public static void main(String[] args) throws FileNotFoundException
    {
        char[] capital = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J','K', 'L', 'M', 'N',
                'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'};

        char[] small = { 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
                'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z' };


        //Input Scanner into the system        
        Scanner scan; 
        //2. Locate file using the scanner class - search to computer data location
        try {
            scan = new Scanner(new File("F:/programming principles/Programming Principles - PART B/enciphered.txt"));
        } catch (Exception e) { //throw exception e (meaning prevent any runtime errors)
            System.out.println("File not found");
            return;
        }
        //3. Set up int's (to count, and for the complete count.)
        //the aplhabet has 26 characters so the new int will be 26. The mem. space of the array.
        int[] count = new int[26];
        int completeTotal = 0;
        //4. Start scanning the system
        //Scan every line and notify user that each line has been read properly. 
        //each time line has been read store value in array and increment by one
        while(scan.hasNextLine()) {
            String line = scan.nextLine();
            System.out.println("Line read: " + line);
            char[] digit = line.toCharArray();
            for(int i = 0; i < digit.length; i++) {
                for(int j = 0; j < 26; j++) {

                    if(digit[i] == capital[j] || digit[i] == small[j]) {
                        count[j]++;
                        completeTotal = completeTotal + 1;
                        break;
                    }
                }
            }
        }
        //5. Display results
        //Print the overall data - letter, frequency and percentage.
        System.out.println("");
        System.out.println("First Word Count"); //notify user of what has been counted? (full count)
        for (int i = 0; i < 26; i++) //increment each letter frequency by one each time
        {
            System.out.print(" " + small[i]);
            System.out.print(" " + count[i]);
            //calculate and display percentage for the full count
            if (count[i] > 0)
                System.out.println(" " + (((float) count[i]/completeTotal)*100) + "%");
            else
                System.out.println(" 0%");

        }
    }    
} //end of source code.

Answer 1

這段代碼就可以了。 inputString是整個文件存儲為單個字符串。 另請注意，如果任何單詞以非字母字符開頭，則會崩潰。 此外，它假定每個單詞都用空格或新行分隔。

    int[] charCounts = new int[26];

    //Separate the string into individual words
    //The string " /n" tells it to look for spaces and newline characters "/n"
    StringTokenizer st = new StringTokenizer(inputString, " /n");

    //Loop until all the words are processed
    while (st.hasMoreTokens()) {

        //Select the next word
        String word = st.nextToken();

        //Convert the string to upper case so that lower case and upper case characters are represented the same
        word = word.toUpperCase();

        //Get the first character from the word
        char firstChar = word.charAt(0);

        //Convert the character to an integer representing it as an ASCII code
        int charCode = (int) firstChar;

        //Increment the count for that character by 1 
        //(We subtract 65 from the ASCII code because the array starts at 0 but 'A' is at 65)
        charCounts[charCode - 65]++;
    }

    //Obviously replace this section with whatever you like. It's just to show you how to get the values out again.
    for (int i = 0; i < charCounts.length; i++){
        System.out.println((char)(i + 65) + ": " + charCounts[i]);
    }

對於字符串“asduhasa ioajsdu ijqwjfoscn kopeurfc eqiwdfjs / nijoasdij iohwefscd aosd8ch”，這輸出：

A: 2
B: 0
C: 0
D: 0
E: 1
F: 0
G: 0
H: 0
I: 4
J: 0
K: 1
L: 0
M: 0
N: 0
O: 0
P: 0
Q: 0
R: 0
S: 0
T: 0
U: 0
V: 0
W: 0
X: 0
Y: 0
Z: 0

如果你有什么不明白的地方，我會盡力解釋。

Answer 2

如何使用正則表達式？ 這是一個樣本..

String line = scan.nextLine();
System.out.println("Line read: " + line);
for(String s : line.split("\\s+")) { 
    System.out.println(s.charAt(0));
    break;
}

Answer 3

只是過度使用substring（）

或者你可以使用charAt（）