Java String.split with multiple character delimeter

Question

I have strings that I need to parse that look like this

"(1,0,quote),(1,0,place),(1,0,hall),(2,0,wall)"

I want to split the string into chunks of triplets so that I get

1,0,quote 
1,0,place 
1,0,hall 
2,0,wall

How can I do this with String.split? If I use a comma as a delimeter, it would split the words too. I want to split them using the delimeter "),(". How do I do this?

Thanks

Use a regex or write a real parser, if you need to handle arbitrarily-nested ()s. Or use a real serialization that already solves this problem: JSON. — Matt Ball
– Matt Ball, Commented Jan 24, 2014 at 21:59
Why not remove the first and last character, then split them by ),( like you said? — crush
– crush, Commented Jan 24, 2014 at 22:00

Pshemo · Accepted Answer · 2014-01-24 22:10:31Z

3

If you split your string with ),( you will not remove ( from start and ) at end of your string. Consider using Pattern and Matcher classes to find elements between ( ).

String text = "(1,0,quote),(1,0,place),(1,0,hall),(2,0,wall)";

Pattern p = Pattern.compile("\\(([^)]+)\\)");
Matcher m = p.matcher(text);
while(m.find()) {
    System.out.println(m.group(1));
}

Output:

1,0,quote
1,0,place
1,0,hall
2,0,wall

If you really want to use split on ),( you will need to manually remove first ( and last ) (splitting will only remove part that should be split on). Also you will have to escape parenthesis ) ( because they are regex metacharacter (for example used to create groups). To do this you can manually add \\ before each of ) and (, or you can surround ),( with \\Q and \\E to mark characters between these elements as literals. BUT you don't have to do this manually. Just use Pattern.quote to produce regex with escaped all metacharacters and use it as split argument like

//I assume that `text` already removed `(` and `)` from its start and end 
String[] array = text.split(Pattern.quote("),("));

edited Jan 24, 2014 at 22:10

answered Jan 24, 2014 at 22:04

Pshemo

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2 Comments

sparkonhdfs Over a year ago

Yeah. I actually made a more specific regex expression (([^,]+[,]){2}[^,]+) . It also rules out instances in which the name has brackets.

Stephan Over a year ago

@Franzd'Anconia A little optimization for the regexp, [,] can be replaced simply by ,.

Stephan · Accepted Answer · 2014-01-24 22:03:24Z

2

With a split method, you'll get an array with one empty cell. Use Pattern and Matcher class instead.

Try this code instead:

String s = "(1,0,quote),(1,0,place),(1,0,hall),(2,0,wall)";
Pattern p = Pattern.compile("\\d+,\\d+,[^)]+");
Matcher m = p.matcher(s);

List<String> l=new ArrayList<>();
while(m.find()) {
    l.add(m.group());
}

System.out.println(l);

Output

[1,0,quote, 1,0,place, 1,0,hall, 2,0,wall]

answered Jan 24, 2014 at 22:03

Stephan

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Comments

dognose · Accepted Answer · 2014-01-24 22:01:30Z

1

As you mentioned, you can split at ),( - then, when iterating over the result array, you only need to take into account, that array[0] contains an additional ( and array[n-1] contains an additional ).

You could also apply a regex to remove the leading and trailing bracket, first or use substring from 1 to n-2 before splitting, etc...

answered Jan 24, 2014 at 22:01

dognose

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