Question

I have the following string “3/4Ton”. I want to split it as –>

word[1] = 3/4 and word[2] = Ton.

Right now my piece of code looks like this:-

Pattern p = Pattern.compile("[A-Z]{1}[a-z]+");
Matcher m = p.matcher(line);
while(m.find()){
    System.out.println("The word --> "+m.group());
    }

It carries out the needed task of splitting the string based on capital letters like:-

String = MachineryInput

word[1] = Machinery , word[2] = Input

The only problem is it does not preserve, numbers or abbreviations or sequences of capital letters which are not meant to be separate words. Could some one help me out with my regular expression coding problem.

Thanks in advance…

Answer 1

You can actually do this in regex alone using look ahead and look behind
(see special constructs on this page: http://java.sun.com/javase/6/docs/api/java/util/regex/Pattern.html )

/**
 * We'll use this pattern as divider to split the string into an array.
 * Usage: myString.split(DIVIDER_PATTERN);
 */
private static final String DIVIDER_PATTERN =

        "(?<=[^\\p{Lu}])(?=\\p{Lu})"
                // either there is anything that is not an uppercase character
                // followed by an uppercase character

                + "|(?<=[\\p{Ll}])(?=\\d)"
        // or there is a lowercase character followed by a digit

        ;

@Test
public void testStringSplitting() {
    assertEquals(2, "3/4Word".split(DIVIDER_PATTERN).length);
    assertEquals(7, "ManyManyWordsInThisBigThing".split(DIVIDER_PATTERN).length);
    assertEquals(7, "This123/4Mixed567ThingIsDifficult"
                        .split(DIVIDER_PATTERN).length);
}

So what you can do is something like this:

for(String word: myString.split(DIVIDER_PATTERN)){
    System.out.println(word);
}

Sean