How can I separate a string for example 36529874 from two to two without having any separation carcter for example 36.52.98.74

Question

I’m taking the IMEI of the phone and I have to divide it into groups of 2 characters for me to convert them to hexa later.

This string comes without separator, the numbers come together, for example 36529874 and I wanted to separate them into groups of two numbers. So I take the String divide the first two and convert into Hexa, divide the two seconds and convert into Hexa, divide the third two and convert into Hexa. After converting these pairs into hexa I want to use only a few to show on the screen. How can I do this? I’m a beginner, I looked for a solution but I couldn’t find.

Answer 1

Can use Regex Java thus:

String test = "36529874";

// regex para números de 2 em 2
// [0-9] = todos os números de 0 a 9
// {2} = agrupar de 2 em 2
// Você poderia também utilizar simplesmente isso: {2}, ele irá pegar de 2 em 2 sem considerar se é numero ou não
Pattern p = Pattern.compile("[0-9]{2}");
Matcher m = p.matcher(test);
List<String> tokens = new LinkedList<String>();
while(m.find())
{
  String token = m.group(0);
  tokens.add(token);
}
for (String string : tokens) {
    System.out.println(string); // out 36 52 98 74
}

Answer 2

Can separate using substring.

String imei = "36529874";
int size = imei.length()/2;
String[] grupos = new String[size];
for (int i = 0; i < size; i++) {
    grupos[i] = imei.substring(i*2, i*2+2);
}

You will have the answer in the vector grupos in order.

See working on Ideone

Answer 3

Since it is a String with a fixed size and the output should follow the same pattern, I suggest making it as simple as possible:

public class ConverteIMEI {
    public static void main(String[] args) {
        String IMEI = "36529874";
        StringBuilder IMEI_convertido = new StringBuilder();
        IMEI_convertido.append(
                Integer.toHexString(Integer.parseInt(IMEI.substring(0, 2)))).
                append(".").append(
                Integer.toHexString(Integer.parseInt(IMEI.substring(2, 4)))).
                append(".").append(
                Integer.toHexString(Integer.parseInt(IMEI.substring(4, 6)))).
                append(".").append(
                Integer.toHexString(Integer.parseInt(IMEI.substring(6, 8))));
        System.out.println("IMEI: " + IMEI + "; IMEI_convertido: " + IMEI_convertido);
    }
}

Exit:

IMEI: 36529874; Imei_converted: 24.34.62.4a

I used Stringbuilder because they are several operations of append() so if you used String, you would create a lot of String objects to concatenate into the result. But as said, because it is a simple problem if using multiple String is also acceptable.

Example in Ideone