How to select a piece of the Java string?

Question

I have the String x = "@646646&".

I’d like to take everything in between @ and & and play in another String. Regardless of what is between these characters being number or not.

How do I do?

Answer 1

Note: The question was edited and with that this answer ended up being invalidated. However, I will keep the answer here because it can still be useful.

Utilize x.replaceAll("(?:[^0-9]+)", ""), where x is your String.

See here an example:

public class Main {
    public static void main (String[] args) {
        String x = "@646646&";
        String z = x.replaceAll("(?:[^0-9]+)", "");
        System.out.println(z);
    }
}

See here working on ideone.

Instead of "(?:[^0-9]+)", you could also use the "(?:[^\\d]+)" which is equivalent.

Answer 2

You can use the methods indexOf() and substring() both of the class String:

public class Teste {
    public static void main(String[] args) {
        String x = "@646646&";
        int indexArroba = x.indexOf("@");
        int indexEComercial = x.indexOf("&");
        String resultado = x.substring(indexArroba + 1, indexEComercial);
        System.out.println(resultado);
    }
}

Exit:

646646

---

Explanation

The method indexOf() returns the position of first occurrence found of String passed as parameter. If no occurrence is found return -1.

The method substring() returns a piece of a String.

Its parameters are:

• int beginIndex : index from where you want this "piece" of String

• int endIndex : index of how far you want that "piece" of String

---

Here you find the official class documentation String.

Answer 3

Still using regular expression you could catch the grouping

public static void main(String args[]) {
    String x = "@646646&";

    Pattern regex = Pattern.compile("@(.+)&");
    //Ou se sempre fosse apenas numeros
    //Pattern regex = Pattern.compile("@(\\d+)&");
    Matcher matcher = regex.matcher(x);

    while (matcher.find()) {
        String resultado = matcher.group(1);
        System.out.println(resultado);
    }
}

Ideone