Quantifier
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Example
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Description
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?+
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X?+
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X, once or not at all
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*+
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X*+
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X, zero or more times
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++
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X++
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X, one or more times
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{n}+
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X{n}+
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X, exactly n times
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{n,}+
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X{n,}+
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X, at least n times
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{n,m}+
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X{n,m}+
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X, at least n but not more than m times
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import java.util.regex.*; import java.io.*; public class RegExHarness { public static void main(String args[]) throws IOException{ BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); Pattern pattern; Matcher matcher; String regex; String text; while(true){ try{ System.out.println("Enter Regular Expression"); regex = br.readLine(); pattern = Pattern.compile(regex); System.out.println("Enter the string"); text = br.readLine(); matcher = pattern.matcher(text); matcher.matches(); System.out.print("I found the text " + matcher.group()); System.out.print(" starting at index " + matcher.start()); System.out.println(" Ending at index " + matcher.end()); } catch(IOException e){ System.out.println(e); } } } }
Sample Output
Enter Regular Expression \d{5}+ Enter the string 98765 I found the text 98765 starting at index 0 Ending at index 5 Enter Regular Expression \d{5,8}+ Enter the string 987654 I found the text 987654 starting at index 0 Ending at index 6 Enter Regular Expression
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