Java / Android regex question

Not sure regular expressions would be my first approach here. Below are my alternatives anyway.

• Using regular expressions (ideone.com demo)

  Matcher m = Pattern.compile("(.*?,.*?,.*?),").matcher(str);
  if (m.find())
      str = m.group(1);
  
  

  
  

• Using indexOf / substring (ideone.com demo)

  str = str.substring(0, str.indexOf(',',
                         str.indexOf(',',
                         str.indexOf(',') + 1) + 1));
  
  

• Using nthOccurrence (ideone.com demo)

  str = str.substring(0, nthOccurrence(str, ',', 2));
  
  

Take a look at Pattern class.

Alternatives: String#split your string or use a StringTokenizer.

Translate s/([^,]*,){3}.+/\1/ into Java regex-ese to truncate after the third comma, s/([^,]*,[^,]*,[^,]*),.+/\1/ to have the truncated portion include the third comma.

int comma = -1;
int n = 0;
do {
    comma = str.indexOf(',', comma + 1);
} while (comma >= 0 && ++n < 3);
if (comma > 0) {
    str = str.substring(0, comma);
} else {
    // third comma not found
}