Regular Expressions: Find pattern in string

Sava :

Somebody can explain how to use regular expression in java. I have few strings 3 :- N, ‘V—g'ufi “ ‘L Total: 13-70 "0- 1‘ i and r _._A_ ,,1 Total: $13.70 i- T«. I need to extract Total: with sum after it: Ex of expected output Total: 13-70, Total: $13.70. I tried to use following code... But as I understand, it will not catch symbols, such as $.-

Pattern p = Pattern.compile("Total: \\d+");
            Matcher m = p.matcher(result);
            while (m.find()) {
                System.out.println(m.group());
            }

Wiktor Stribiżew :

You may use

Total:\s*\$?\d+(?:[-.]\d+)?

See the regex demo.

Details

• Total: - a literal substring
• \s* - 0+ whitespaces
• \$? - an optional $ char
• \d+ - 1+ digits
• (?:[-.]\d+)? - an optional non-capturing group matching 1 or 0 occurrences of:
  • [-.] - either - or .
  • \d+ - 1 or more digits.

In Java:

Pattern p = Pattern.compile("Total:\\s*\\$?\\d+(?:[-.]\\d+)?");

If you need to extract the value use a capturing group round the pattern you need to extract (here, \$?\d+(?:[-.]\d+)?, for example) and access the group value like

Pattern p = Pattern.compile("Total:\\s*(\\$?\\d+(?:[-.]\\d+)?)");
Matcher m = p.matcher(result);
while (m.find()) {
     System.out.println(m.group(1));
}