Java regex match not working

Question

I am trying to match string using java regex, but my match is failing. What may be the issue in code below?

String line = "Copy of 001";

boolean b = Pattern.matches("001", line);

System.out.println("value is : "+b);

Output value is

value is : false

You don't need `matches` here, use `contains`, unless you want to match a sequence of zeros that ends with 1. — Maroun, Jun 20 '15 at 10:27
possible duplicate of [Difference between matches() and find() in Java Regex](http://stackoverflow.com/questions/4450045/difference-between-matches-and-find-in-java-regex) — Joe, Jun 20 '15 at 10:35

JB Nizet · Answer 1 · 2015-06-20T10:29:23.673

1

matches() tests if the whole string matches the regex. It doesn't. Use Matcher.find() instead. Or simply use String.contains(), as you don't need a regex to match a literal sequence of characters.

edited Jun 20 '15 at 10:29

answered Jun 20 '15 at 10:26

JB Nizet

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Thank you got it,, i would have used "*.001" – Sunil Kumar Jun 20 '15 at 10:28
No, that would be an invalid regex. `.*001` would work. But don't use regexes where simple contains() call work fine (and are simpler and more efficient). – JB Nizet Jun 20 '15 at 10:30

score 1 · Answer 2 · answered Jun 20 '15 at 10:27

matches will match the whole string. Use a Matcher and the find() method instead:

boolean b = Pattern.compile("001").matcher(line).find();

Or make your pattern more flexible and allow it to have something prefixing the "001". For example:

".*001"

For something this simple, though, Pattern is an overkill and a simple indexOf will do the job much more efficiently:

boolean b = line.indexOf("001") > -1;

Java regex match not working

2 Answers2