Is there any simple way to convert camel-case to snake-case correctly?-CodePudding

I tried as the below code code snippet, but the TradeID is printing as Trade_I_D, but it must be as Trade_ID.

input: getCurrency, getAccountName, getTradeID
expected output: Currency, Account_Name, Trade_ID

public class RemoveGet {

    public static void main(String args[]) {
        for (String a : args) {
            String b = a.replace("get", "");
            //System.out.println(b);
            StringBuffer sb = new StringBuffer();
            for (int i = 0; i < b.length(); i  ) {
                if (Character.isUpperCase(b.charAt(i))) {
                    sb.append("_");
                    sb.append(b.charAt(i));
                } else {
                    sb.append(b.charAt(i));
                }
            }
            //System.out.println(sb.toString());
            String c = sb.toString();
            if (c.startsWith("_")) {
                System.out.println(c.substring(1));
            }
        }
    }
}

CodePudding user response：

Use a boolean first-time switch to only put an underscore after the second upper case letter.

Here are some test results.

getTradeID
Trade_ID

Here's the complete runnable code.

public class RemoveGet {

    public static void main(String args[]) {
        args = new String[1];
        args[0] = "getTradeID";
        
        for (String a : args) {
            System.out.println(a);
            String b = a.replace("get", "");
            boolean firstTimeSwitch = true;
//          System.out.println(b);
            StringBuffer sb = new StringBuffer();
            sb.append(b.charAt(0));
            
            for (int i = 1; i < b.length(); i  ) {
                if (firstTimeSwitch && Character.isUpperCase(b.charAt(i))) {
                    sb.append("_");
                    sb.append(b.charAt(i));
                    firstTimeSwitch = false;
                } else {
                    sb.append(b.charAt(i));
                }
            }
            
            System.out.println(sb.toString());
        }
    }

}

CodePudding user response：

try this

str = str.replace("get", "")
    .replaceAll("([A-Z] )([A-Z][a-z])", "$1_$2")
    .replaceAll("([a-z])([A-Z])", "$1_$2")

CodePudding user response：

Instead of writing all logic in the main function, write some functions to do small tasks and call them in the main function. This makes the code readable and easy to debug. This could be the possible solution code:

public class RemoveGet {

 public static String addUnderScoreAppropriately(String input) {
     String result = "";
     String underScore = "_";
     for(int i=0; i<input.length();i  ) {
         if((Character.isUpperCase(input.charAt(i))) && (i != 0)) {
             result = result   underScore   input.charAt(i);
         }else{
             result = result   input.charAt(i);
         }
     }
     result = result.replace("_I_D","_ID");
     return result;
 }

 public static void main(String args[]) {
    for (String a : args) {
        System.out.println(addUnderScoreAppropriately(a.replace("get","")));
    }
 }

}