Spliting a sentence when a hyphen is encountered in java

Question

I have following code in my program. It splits a line when a hyphen is encountered and stores each word in the String Array 'tokens'. But I want the hyphen also to be stored in the String Array 'tokens' when it is encountered in a sentence.

String[] tokens = line.split("-");

The above code splits the sentence but also totally ignores the hyphen in the resulting array. What can I do to store hyphen also in the resulting array?

cant you manually add the hyphen? also if suppose you have "abc-xyz" then you want hyphen with abc like "abc-" or with xyz like "-xyz" — Bhavik Shah, Nov 28 '12 at 09:29
You don't say where you want the hyphen. As a separate element or attached to a word ? — Brian Agnew, Nov 28 '12 at 09:30
Maybe this solution helps you: http://stackoverflow.com/questions/275768/is-there-a-way-to-split-strings-with-string-split-and-include-the-delimiters — Romczyk, Nov 28 '12 at 09:31
@SuneetaSingh. What result do you want for : - `"asdf asdf abc - asdf adf"`? — Rohit Jain, Nov 28 '12 at 09:35
@RohitJain I want result like: "asdf","asdf","abc","-","asdf","asdf" — Suneeta Singh, Nov 28 '12 at 09:38
@SuneetaSingh.. Ok, then your question was rather a little confusing. Still I have added a solution for that in my answer too. — Rohit Jain, Nov 28 '12 at 09:41
@RohitJain what about "abc- def"? It gives "abc", "-", " def". What can be done to get "abc", "-", "def"? — Sujan, Nov 28 '12 at 09:46

Rohit Jain · Accepted Answer · 2012-11-28T09:52:00.197

1

Edit : -

Seems like you want to split on both whitespaces and hyphen but keeping only the hyphen in the array (As, I infer from your this line - stores each word in the String Array), you can use this: -

String[] tokens = "abc this is-a hyphen def".split("((?<=-)|(?=-))|\\s+");
System.out.println(Arrays.toString(tokens));

Output: -

[abc, this, is, -, a, hyphen, def]

For handling spaces before and after hyphen, you can first trim those spaces using replaceAll method, and then do split: -

"abc this is - a hyphen def".replaceAll("[ ]*-[ ]*", "-")
                            .split("((?<=-)|(?=-))|\\s+");

Previous answer : -

You can use this: -

String[] tokens = "abc-efg".split("((?<=-)|(?=-))");
System.out.println(Arrays.toString(tokens));

OUTPUT : -

[abc, -, efg]

It splits on an empty character before and after the hyphen (-).

edited Nov 28 '12 at 09:52

answered Nov 28 '12 at 09:30

Rohit Jain

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And if there are no empty chars? – Romczyk Nov 28 '12 at 09:31
This doesn't split space-separated words though, does it ? – Brian Agnew Nov 28 '12 at 09:31
@Romczyk.?? There is always one. – Rohit Jain Nov 28 '12 at 09:31
@BrianAgnew.. It will, but it will include the space in the previous and next word. – Rohit Jain Nov 28 '12 at 09:32
@BrianAgnew.. For e.g for `"abc - efg"` it will give: - `[abc , -, efg]`. Note the space after `abc` and `efg`. – Rohit Jain Nov 28 '12 at 09:32
"abc this is-a hyphen def".split("((?<=-)|(?=-))") gives me a three-element array as a result – Brian Agnew Nov 28 '12 at 09:33
@BrianAgnew.. Well, OP is splitting on just `hiephen`, I assumed. – Rohit Jain Nov 28 '12 at 09:34
@BrianAgnew.. To also split on space, you can add a `space` in split criteria also: - `"((?<=-)|(?=-))|\\s+"` – Rohit Jain Nov 28 '12 at 09:36

Robe Elckers · Answer 2 · 2012-11-28T10:00:31.543

0

I suggest to use a regular expression in combination with the Java Pattern and Matcher. Example:

String line = "a-b-c-d-e-f-";
Pattern p = Pattern.compile("[^-]+|-");
Matcher m = p.matcher(line);
while (m.find())
{
  String match = m.group();
  System.out.println("match:" + match);
}

To test your regular expression you could use an online regexp tester like this

edited Nov 28 '12 at 10:00

answered Nov 28 '12 at 09:33

Robe Elckers

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Spliting a sentence when a hyphen is encountered in java

2 Answers2