Python to Java code conversion

Question

Could anyone give me a hand converting this Python script to Java?

This is the code

theHex = input("Hex: ").split() 
theShift = int(input("Shift: ")) 
result = "" 
for i in range (len(theHex)): 
    result += (hex((int(theHex[i],16) + theShift))).split('x')[1] + " " 
    print(result)

Here is what I've got

System.out.print("Please enter the hex: ");
String theHex = BIO.getString();
String[] theHexArray = theHex.split(" ");

System.out.print("Please enter the value to shift by: ");
int theShift = BIO.getInt();

String result[] = null;

for( int i = 0 ; i < theHex.length() ; i++ ){
     //result += (hex((int(theHex[i],16) + theShift))).split('x')[1] + " "
}

toText(result[]);

BIO is a class I have to collect Strings and Ints. Think of it as basically a scanner.

Could anyone help me translate the last line?

EDIT Here is the toText method

public static void toText(String theHexArray[]){
    String theHex = "";

    for(int i = 0 ; i < theHexArray.length ; i++ ){
        theHex += theHexArray[i];
    }

    StringBuilder output = new StringBuilder();
    try{
        for (int i = 0; i < theHex.length(); i+=2){
            String str = theHex.substring(i, i+2);
            output.append((char)Integer.parseInt(str, 16));
        }
    }catch(Exception e){
        System.out.println("ERROR");
    }
    System.out.println(output);
}

Answer 1

I suspect you're making this rather more work for yourself than you really need to, but here goes.

If you're going to go for a line-by-line port, then do that .

1. Don't declare result as an array of strings. That'll just give you a headache. Make it either a StringBuilder or a plain String as I do here ( StringBuilder will be more efficient, admittedly, but this is probably easier to understand). This is also more similar to the python code you already have.

2. Understand what your python code is doing. It's taking a string in hex format, parsing it to an integer, adding a value ( theShift ), converting back into hex, and then getting just the numeric part of the string (without the leading 0x ). So in Java, that loop goes like this. ( NOTE : in Java Integer.toString(x, 16) does not print the leading 0x , so we don't need to chop it off).

    String result = ""; for (String thisHex : theHexArray) { result += Integer.toString(Integer.parseInt(thisHex, 16) + theShift, 16) + " "; } 

3. Lose the toText method. At this point you have the string you wanted, so that method doesn't really do anything anymore.

Answer 2

Regardless of whether you decide to translate line by line, or work on understanding the code and then write a Java based solution to the problem, you need to break down that last line to understand it. Try looking at it like this:

result += (hex((int(theHex[i],16) + theShift))).split('x')[1] + " " 

is the same as -

val1 = int(theHex[i],16)
val2 = (val1 + theShift)
val3 = hex(val2)
val4 = (val3).split('x')
result += val4[1] + " " 

Now you can see more clearly what is being called. Your next step is to look up what the int, hex and split calls are doing.