Export all braces in a String to an array

Question

example:

String = "(a(b[}7cv)))"

the array should look like this: ["(","(","[","}",")",")",")"]

my try:

if(s.charAt(i) == "(" ){
    //add to array}

Im a Java beginner. I tried searching the string with an for-loop but cant get it to work. — Zireal, Dec 05 '18 at 12:19
Try this https://stackoverflow.com/help/how-to-ask and help us — Arun Sudhakaran, Dec 05 '18 at 12:19
i want to ignore everything except the braces in a string and write them in an array — Zireal, Dec 05 '18 at 12:20
Assuming `String brackets = "()[]{}";` you can just do `"(a(b[}7cv)))".chars().mapToObj(ch -> String.valueOf((char) ch)).filter(brackets::contains).toArray(String[]::new)`. — Ole V.V., Dec 05 '18 at 13:10

score 1 · Answer 1 · answered Dec 05 '18 at 12:24

You can simply find them using regex and add them to a List

  public static void main(String[] args) {
    String foo = "(a(b[}7cv)))";
    List<String> allMatches = new ArrayList<String>();
    Matcher m = Pattern.compile("\\W")
        .matcher(foo);
    while (m.find()) {
      allMatches.add(m.group());
    }
    System.out.println(allMatches); 
  }

If it's only brackets you're after, you might want to take "[(){}\\]\\[]" as a regex for Pattern.compile

score 0 · Answer 2 · answered Dec 05 '18 at 12:34

How about getting non alphanumeric and add to the list

String s = "(a(b[}7cv)))";

    Pattern p = Pattern.compile("[^a-z0-9 ]", Pattern.CASE_INSENSITIVE);
    Matcher m = p.matcher(s);
    var list = new ArrayList<String>();

    while (m.find()) {
        list.add(String.valueOf(s.charAt(m.start())));
    }
    System.out.println(Arrays.toString(list.toArray()));

Output

[(, (, [, }, ), ), )]

Export all braces in a String to an array

2 Answers2