I have a string which contains a sentence and I want to split it in half, based on a word.
I have the regex (\\w+) word which I thought would get me all the words before "word" + "word" itself, then I could just remove the last four chars.
However this doesn't seem to work.. any ideas what I've done wrong?
Thanks.
This seems to work:
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Test {
public static void main(String[] args) {
Pattern p = Pattern.compile("([\\w\\s]+) word");
Matcher m = p.matcher("Could you test a phrase with some word");
while (m.find()) {
System.err.println(m.group(1));
System.err.println(m.group());
}
}
}
Using string manipulation:
int idx = sentence.indexOf(word);
if (idx < 0)
throw new IllegalArgumentException("Word not found.");
String before = sentence.substring(0, idx);
Using regex:
Pattern p = Pattern.compile(Pattern.quote(word));
Matcher m = p.matcher(sentence);
if (!m.find())
throw new IllegalArgumentException("Word not found.");
String before = sentence.substring(0, m.start());
Alternatively:
Pattern p = Pattern.compile("(.*?)" + Pattern.quote(word) + ".*");
Matcher m = p.matcher(sentence);
if (!m.matches())
throw new IllegalArgumentException("Word not found.");
String before = m.group(1);
You will want to tokenize each part of the sentence before and after the word.
http://docs.oracle.com/javase/1.5.0/docs/api/
String[] result = "this is a test".split("\\s"); //replace \\s with your word
for (int x=0; x<result.length; x++)
System.out.println(result[x]);
Try this:
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Test {
public static void main(String[] args) {
Pattern p = Pattern.compile("^.*?(?= word)");
Matcher m = p.matcher("Everything before the word");
while (m.find()) {
System.out.println(m.group());
}
}
}
It breaks down as follows:
.*? everything
(?= before
word
) end
The reason is that + is a greedy quantifier and will match the entire String including the word you specify, without giving back.
If you change it to (\\w+?) word it should work (reluctant quantifier). More on quantifiers and their exact function here.
+ is greedy, but it does allow backtracking. The possessive equivalent is ++word he was looking for...