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Technical Article => Programming =>  Java

Greedy and Nongreedy Matching in a Regular Expression

  Example Depot      2011-08-09 12:42:28      1,879    0    0

By default, pattern matching is greedy, which means that the matcher returns the longest match possible. For example, applying the pattern A.*c to AbcAbcA matches AbcAbc rather than the shorter Abc. To do nongreedy matching, a question mark must be added to the quantifier. For example, the pattern A.*?c will find the shortest match possible.
// Greedy quantifiers
String match = find("A.*c", "AbcAbc");  // AbcAbc
match = find("A.+", "AbcAbc");          // AbcAbc

// Nongreedy quantifiers
match = find("A.*?c", "AbcAbc");        // Abc
match = find("A.+?", "AbcAbc");         // Abc

// Returns the first substring in input that matches the pattern.
// Returns null if no match found.
public static String find(String patternStr, CharSequence input) {
    Pattern pattern = Pattern.compile(patternStr);
    Matcher matcher = pattern.matcher(input);
    if (matcher.find()) {
        return matcher.group();
    }
    return null;
}


Source : http://www.exampledepot.com/egs/java.util.regex/Greedy.html

REGULAR EXPRESSION PATTERN MATCH GREEDY

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