import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Example {
public static void main(String[] args) {
final String regex = "box(?!-shadow) ";
final String string = "positive lookahead\n"
+ "box(?=-shadow)\n\n"
+ "https://youtu.be/aIEjh0YsxWA?t=309\n"
+ "// select box only if what comes after it IS -shadow\n\n"
+ "box-sizing\n"
+ "shape-shadow\n"
+ "------------------------------------------------------------------\n"
+ "negative lookahead\n"
+ "box(?!-shadow) \n\n"
+ "// select box only if what comes after it IS NOT shadow\n\n"
+ "box-sizing\n"
+ "shape-shadow\n\n"
+ "------------------------------------------------------------------\n"
+ "negative look behind\n"
+ "(?<!jeffery).+\n\n"
+ "https://youtu.be/aIEjh0YsxWA?t=212\n"
+ "// this string cannot come before the @\n\n"
+ "jeffrey@envato.com\n"
+ "joe@envato.com\n\n"
+ "------------------------------------------------------------------\n"
+ "positive look behind\n"
+ "(?<=box-)sizing\n\n"
+ "https://youtu.be/aIEjh0YsxWA?t=337\n"
+ "// only want to select 'sizing' if what comes before it is 'box' \n"
+ "// select sizing as long as what comes before it is 'box'\n\n"
+ "box-sizing\n"
+ "shape-sizing\n\n"
+ "------------------------------------------------------------------\n\n"
+ "negative look behind\n"
+ "(?<!box-)sizing\n\n"
+ "// anything can come before it except 'box'\n\n"
+ "box-sizing\n"
+ "shape-sizing\n\n"
+ "-----------------------------------------------------------------\n"
+ "positive lookahead \n"
+ "@.+(?=\\.[a-z]{2,4})\n\n"
+ "// Matches a group after your main expression without including it in the result\n\n"
+ "wilson@gmail.com\n"
+ "frank@france.fr\n"
+ "joe@paris.france\n\n";
final Pattern pattern = Pattern.compile(regex);
final Matcher matcher = pattern.matcher(string);
while (matcher.find()) {
System.out.println("Full match: " + matcher.group(0));
for (int i = 1; i <= matcher.groupCount(); i++) {
System.out.println("Group " + i + ": " + matcher.group(i));
}
}
}
}
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Java, please visit: https://docs.oracle.com/javase/7/docs/api/java/util/regex/Pattern.html