CODEWITHSUNDEEP
javaregex
Tzupy
Tzupy

Reputation: 23

Java regex get all matching groups

I'm trying to parse an input string of type "move 2 up;1 right;1 down" using a regex, but I can't seem to figure out how to get all groups of commands while ignoring the "move" keyword.

My regex is:

(?:\bmove\b) ((?<amount>[1-6]) (?<direction>(\bup\b|\bright\b|\bdown\b|\bleft\b))(?:;?))+

and my Java code is this:

String str = "move 1 right;2 left;";
String regex = "(?:\\bmove\\b) ((?<amount>[1-6]) (?<direction>(\\bup\\b|\\bright\\b|\\bdown\\b|\\bleft\\b))(?:;?))+";
Pattern pattern = Pattern.compile(regex, Pattern.CASE_INSENSITIVE);
Matcher match = pattern.matcher(str);
while (match.find()) {
    String group = match.group(1);
    System.out.println(group);
}

In the loop I would like to get the first command as "1 right" and the second as "2 left". With the regex that I have now I only get the "2 left;". There are some examples of input here: https://regex101.com/r/Fg0hk3/3.

How do I fix my regex?

Ended up using 2 regex patterns, one for the full match and one for the tokens:

Full match:

(?:\bmove\b) ((?<amount>[1-6]) (?<direction>(\bup\b|\bright\b|\bdown\b|\bleft\b))(?:;?))+

Tokens:

(?<amount>[1-6]) (?<direction>(?:\bup\b|\bright\b|\bdown\b|\bleft\b))

Upvotes: 2

Views: 6330

Answers (1)

Adam
Adam

Reputation: 3965

The simplest way to do this is to create a regular expression to match only the part you need (number and direction) without "move" or the semicolons. Then match it to the string and add all groups to a list.

String str = "move 55 up;2 right;100 down;8 left";
String regex = "(\\d+ (?:up|down|left|right))";
List<String> matches = new ArrayList<String>();
Matcher m = Pattern.compile(regex).matcher(str);

while (m.find()) {
    matches.add(m.group());
}

System.out.println(matches);
// Output: [55 up, 2 right, 100 down, 8 left]

Upvotes: 4

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