How to remove all character from a string until a range of accepted characters?

Question

For example, I have a string "0.01" . How can I get "1" ?

I had tried

String a = "0.01"
a = a.replaceAll(".", "");
a = a.replaceAll("0", "");

but this won't work as the string can be "0.0105" and in this case, I want to keep "105"

I also tried

String a = "0.01"
b = a.substring(s.indexOf("0")+3);

this also won't work as the string can be "0.1" which I want to keep "1"

In short, I want to remove all 0 or . until it starts with non-0. The string is actually converted from Double. I can't simply *100 with the Double as it can be 0.1

Answer 1

    String a = "0.01";
    String[] b = a.split("\\.");
    a = b[0]+b[1];
    
    int c = Integer.parseInt(a);

You will get 1 as integer. When you want to add something you can add and then return to string like:

    c = c+3;        
    String newa = String.valueOf(c);
    System.out.println(newa);

Answer 2

Just do:

System.out.println(Integer.valueOf(testCase.replace(".", "")));

Credit to YCF_L

Answer 3

Use the regex, [1-9][0-9]* which means the first digit as 1-9 and then subsequent digits ( optional ) as 0-9 . Learn more about regex from Lesson: Regular Expressions .

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Main {
    public static void main(String[] args) {
        String str = "0.0105";
        Pattern pattern = Pattern.compile("[1-9][0-9]*");
        Matcher matcher = pattern.matcher(str);
        if (matcher.find()) {
            str = matcher.group();
        }

        System.out.println(str);
    }
}

Output:

105