Java String Break by space after position

Question

I have a lengthy string and want to break it up into a number of sub-strings so I can display it in a menu as a paragraph rather than a single long line. But I don't want to break it up in the middle of a word (so a break every n characters won't work).

So I want to break the string up by the first occurrence of any of the characters in a String after a certain point (in my case, the characters would be a space and a semi-colon, but they could be anything).

Something like:

String result[] = breakString(baseString, // String
                              lineLength, // int
                              breakChars) // String

Possibly related: [split a string in java into equal length substrings while maintaining word boundaries](http://stackoverflow.com/questions/25853393/split-a-string-in-java-into-equal-length-substrings-while-maintaining-word-bound) — Pshemo, Jan 23 '16 at 02:46
Do you really want to break the string after a certain point, so every line contains __at least__ `lineLength` characters? Or the paragraph should contain that __at most__, breaking after the last occurence of `breakChars` in `lineLength` characters? — bal, Jan 24 '16 at 23:13

score 0 · Answer 1 · answered Jan 23 '16 at 02:47

0

Consider splitting by the break chars first and then summing the lengths of the segments that result from that split until you reach your line length.

answered Jan 23 '16 at 02:47

Hamel Kothari

717
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Lucas Ross · Answer 2 · 2016-01-23T04:08:26.277

Here is one way. I took "by the first occurrence of any of the characters in a String after a certain point" to mean that the next instance of breakChars after a certain lineLength should be the end of a line. So, breakString("aaabc", 2, "b") would return {"aaab", "c"}.

static String[] breakString(String baseString, int lineLength, String breakChars) {
    // find `lineLength` or more characters of the String, until the `breakChars` string
    Pattern p = Pattern.compile(".{" + lineLength + ",}?" + Pattern.quote(breakChars));

    Matcher m = p.matcher(baseString);
    List<String> list = new LinkedList<>();
    int index = 0;
    while (m.find(index)) {
        String s = m.group();
        list.add(s);

        // find another match starting at the end of the last one
        index = m.end();
    }

    if (index < baseString.length() - 1) {
        list.add(baseString.substring(index));
    }

    return list.toArray(new String[list.size()]);
}

Java String Break by space after position

2 Answers2

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