Good way to check if a String ends with a Regex String

Question

I need to check if a given String ends with a Regular Expression String. I have written the following code:

public static void main(String[] args) {
    String str = "wf-008-dam-mv1";
    String regex = "mv(\\d)?$";
    Pattern pattern = Pattern.compile(regex);
    Matcher matcher = pattern.matcher(str);

    if(matcher.find() && matcher.end() == str.length()) {
        System.out.println("Ends with true");
    } else {
        System.out.println("Ends with false");
    }
}

Here the str can ends with or without number. Is it a good way to do it?

NPE · Accepted Answer · 2014-09-03 12:00:45Z

4

That's a pretty reasonable way to do it, except that the matcher.end() == str.length() check is redundant. The $ regex anchor already takes care of that.

edited Sep 3, 2014 at 12:00

answered Sep 3, 2014 at 11:55

NPE

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Holger · Accepted Answer · 2014-09-03 12:10:50Z

3

Since the $ anchor already ensures that the pattern must match at the end, a simple find is enough; you don’t need to verify the end of the match. If you prepend your pattern with .* you can use matches rather than find which allows you to remove the entire boilerplate:

boolean endsWith="wf-008-dam-mv1".matches(".*mv(\\d)?$");
System.out.println("Ends with "+endsWith);

That’s all you need…

answered Sep 3, 2014 at 12:10

Holger

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Comments

Vinay Veluri · Accepted Answer · 2014-09-03 12:00:50Z

1

matcher.find() does the job for you and no need to check with matcher.end() == str.length()

API says

If the match succeeds then more information can be obtained via the start, end, and group methods

answered Sep 3, 2014 at 12:00

Vinay Veluri

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