將電話號碼中的所有字母轉換為數字

Question

我試圖用國際標准字母/數字映射用數字替換每個字母。 我的輸出正確運行但是，如何讓電話號碼中的破折號自動出現在輸出中？ 例如，如果我輸入1800Flowers，則打印出18003569377.如何在不使用正則表達式的情況下將其打印為1-800-3569377？

import java.util.Scanner;

public class PhoneKeypad {

public static void main(String[] args) {

    Scanner input = new Scanner(System.in);

    //while loop keeps the program running until the user enters quit 
    while (true) {
        System.out.println("\nEnter a phone number or quit to exit:");
        String phoneNumber = input.next();

        if (phoneNumber.equalsIgnoreCase("quit")) {              
            System.out.print("\nProgrammed by me");
            return;
        }

        //checks if the phone number entered is at least 8 digits
        if (phoneNumber.length() < 8) {
            System.out.println("Invalid Phone Number");

        } else {

            System.out.println(getNumber(phoneNumber));
        }
    }

}

//method converts all letters in the phone number to digits
public static String getNumber(String phoneNumber) {

    int keypadNum = 0;

    for (int i = 0; i < phoneNumber.length(); i++) {
        char letter = phoneNumber.charAt(i);

        if (Character.isAlphabetic(letter)) {
            letter = Character.toUpperCase(letter);

            switch (letter) {
                case 'A':
                case 'B':
                case 'C':
                    keypadNum = 2;
                    break;
                case 'D':
                case 'E':
                case 'F':
                    keypadNum = 3;
                    break;
                case 'G':
                case 'H':
                case 'I':
                    keypadNum = 4;
                    break;
                case 'J':
                case 'K':
                case 'L':
                    keypadNum = 5;
                    break;
                case 'M':
                case 'N':
                case 'O':
                    keypadNum = 6;
                    break;
                case 'P':
                case 'Q':
                case 'R':
                case 'S':
                    keypadNum = 7;
                    break;
                case 'T':
                case 'U':
                case 'V':
                    keypadNum = 8;
                    break;
                case 'W':
                case 'X':
                case 'Y':
                case 'Z':
                    keypadNum = 9;
                    break;
                default:
                    System.out.println("Invalid phone number");
            }

            phoneNumber = phoneNumber.substring(0, i) + keypadNum + phoneNumber.substring(i + 1);
        }
    }

    return phoneNumber;
}
}

預期產出：

Answer 1

您可以使用String.replaceAll的正則表達式 。 刪除前導的一個，分組前三個數字，后三個數字和最后一組數字。 就像是

public static String formatNumber(String phoneNumber) {
    if (phoneNumber.startsWith("1")) {
        phoneNumber = phoneNumber.substring(1);
    }
    return phoneNumber.replaceAll("(\\d{3})(\\d{3})(\\d+)", "1-$1-$2-$3");
}

要么

public static String formatNumber(String phoneNumber) {
    return phoneNumber.replaceAll("1(\\d{3})(\\d{3})(\\d+)", "1-$1-$2-$3");
}

然后稱之為

System.out.println(formatNumber(getNumber(phoneNumber)));

我用1800flowers跑了它（如預期的那樣）

1-800-356-9377

或者沒有正則表達式

public static String formatNumber(String phoneNumber) {
    if (phoneNumber.startsWith("1")) {
        phoneNumber = phoneNumber.substring(1);
    }
    return "1-".concat(phoneNumber.substring(0, 3)) //
            .concat("-").concat(phoneNumber.substring(3, 6)) //
            .concat("-").concat(phoneNumber.substring(6));
}

在調用formatNumber之前，您可以刪除破折號以使用類似的東西對其進行標准化

public static String removeDashes(String phoneNumber) {
    StringBuilder sb = new StringBuilder();
    for (char ch : phoneNumber.toCharArray()) {
        if (ch != '-') {
            sb.append(ch);
        }
    }
    return sb.toString();
}

然后

System.out.println(formatNumber(removeDashes(getNumber(phoneNumber))));