Java: parse int value from a char

Question

I just want to know if there\'s a better solution to parse a number from a character in a string (assuming that we know that the character at index n is a number).

Answer 1

Using binary AND with 0b1111:

String element = "el5";

char c = element.charAt(2);

System.out.println(c & 0b1111); // => '5' & 0b1111 => 0b0011_0101 & 0b0000_1111 => 5

// '0' & 0b1111 => 0b0011_0000 & 0b0000_1111 => 0
// '1' & 0b1111 => 0b0011_0001 & 0b0000_1111 => 1
// '2' & 0b1111 => 0b0011_0010 & 0b0000_1111 => 2
// '3' & 0b1111 => 0b0011_0011 & 0b0000_1111 => 3
// '4' & 0b1111 => 0b0011_0100 & 0b0000_1111 => 4
// '5' & 0b1111 => 0b0011_0101 & 0b0000_1111 => 5
// '6' & 0b1111 => 0b0011_0110 & 0b0000_1111 => 6
// '7' & 0b1111 => 0b0011_0111 & 0b0000_1111 => 7
// '8' & 0b1111 => 0b0011_1000 & 0b0000_1111 => 8
// '9' & 0b1111 => 0b0011_1001 & 0b0000_1111 => 9