如何替換字符串中的字符並將其轉換爲double？

Question

2維數組是純粹參考的。我需要知道如何用相應的整數替換字符串中的字符並以雙重格式顯示它。例如conversionTable --->[Input: "ab.a" , Output: "1.0"]或[Input: "a.jjj" , Output: "0.999"]。我試圖實現這個通過開關的情況下，但它會給出錯誤。我怎樣才能實現這個直通開關案例或更有效？

package practice; 

import java.util.Scanner; 
import java.lang.Double; 
public class Decrypt { 

private static String conversionTable[][] = { 
     {"a", "0"}, 
     {"b", "1"}, 
     {"c", "2"}, 
     {"d", "3"}, 
     {"e", "4"}, 
     {"f", "5"}, 
     {"g", "6"}, 
     {"h", "7"}, 
     {"i", "8"}, 
     {"j", "9"}, 
}; 

public static double decrypt(String encryptedNumber) { 

String input = encryptedNumber; 

switch(input.length()){ 

case 'a': 
System.out.print(input.replace('a', '0')); 
break; 

case 'b': 
System.out.print(input.replace('b','1')); 
break; 

case 'c': 
System.out.print(input.replace('c', '2')); 
break; 

case 'd': 
System.out.print(input.replace('d','3')); 
break; 

case 'e': 
System.out.print(input.replace('e','4')); 
break; 

case 'f': 
System.out.print(input.replace('f','5')); 
break; 

case 'g': 
System.out.print(input.replace('g','6')); 
break; 

case 'h': 
System.out.print(input.replace('h','7')); 
break; 

case 'i': 
System.out.print(input.replace('i','8')); 
break; 

case 'j': 
System.out.print(input.replace('j','9')); 
break; 
} 


Double d = new Double(""); 
double result = Double.parseDouble(input); 
return result; 


} 

public static void main(String arg[]){ 

Scanner scanner =new Scanner(System.in); 
System.out.println("Enter the string to decrypt:"); 
String input=scanner.next(); 
System.out.println("Number after decryption is:"+decrypt(input)); 

} 

} 

Answer 1

我會使用與(char) ('0' + (ch - 'a'))東西，因爲我們知道這是一個'是 'A' 和 'B' - 'A' 應該是 '1'。例如，

private static String decryptString(String en) { 
    if (en == null) { 
    return ""; 
    } 
    en = en.trim().toLowerCase(); 
    StringBuilder sb = new StringBuilder(); 
    for (char ch : en.toCharArray()) { 
    if (ch >= 'a' && ch <= 'j') { 
     sb.append((char) ('0' + (ch - 'a'))); 
    } else { 
     sb.append(ch); 
    } 
    } 
    return sb.toString(); 
} 

public static Double decrypt(String encryptedNumber) { 
    return Double.valueOf(decryptString(encryptedNumber)); 
} 

public static void main(String[] args) { 
    System.out.println(decrypt("ab.a")); 
    System.out.println(decrypt("a.jjj")); 
} 

輸出是（的要求）

1.0 
0.999 

Answer 2

剛剛寫了一個非常難看：

public static void main(String[] args) { 
    String[] index = {"a","b","c","d","e","f","g","h","i","j"}; 

    String str= "ab.a"; 
    String strNew = str; 
    for(int i=0;i<index.length;i++){ 
     strNew = strNew.replaceAll(index[i], String.valueOf(i)); 
    } 

    System.out.println(Double.parseDouble(strNew)); 
}