在Java中使用正则表达式提取子字符串

Question

I am using a regex to extract the gold quotes from a webpage. I am parsing it to a string, then using regex to extract the quotes.

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

public class HelloWorld{

 public static void main(String []args){
     String str = "----------------------------------------------------------------------"
                + "Metals          Bid        Ask           Change        Low       High "
                + "----------------------------------------------------------------------"
                + "Gold         1176.40     1177.40     -8.60  -0.73%    1171.90  1183.90";

    Pattern pattern = Pattern.compile("Gold(\\s{9})(\\d{4}).(\\d{2})");
    Matcher matcher = pattern.matcher(str);

    if (matcher.find())
    {
        System.out.println(matcher.group());
    }
    else {
        System.out.println("No string found");
    }

    }
}

This code finds the "Gold 1176.40" string that I want, but I can't save it as another string, as in

String temp = matcher.group();

How can I do this?

Answer 1

Declare a temp variable before the if condition and then append the matched string to that temp variable.

String temp = "";
Pattern pattern = Pattern.compile("Gold(\\s{9})(\\d{4})\\.(\\d{2})");
Matcher matcher = pattern.matcher(str);

if (matcher.find())
{
    temp = temp + matcher.group();
}
else {
    System.out.println("No string found");
}

Answer 2

If you are interest do it in single line.

String str = "----------------------------------------------------------------------"
                + "Metals          Bid        Ask           Change        Low       High "
                + "----------------------------------------------------------------------"
                + "Gold         1176.40     1177.40     -8.60  -0.73%    1171.90  1183.90";
String s = str.substring(str.indexOf("Gold"))).replaceAll("(Gold\\s{9}\\d{4}.\\d{2}).*", "$1");