I am trying to use matcher as an expression to find time stamps in my list of strings. Ex (" [00:00:00.000] ") There are white spaces before and after the time stamp
I checked my regex online and it say it is correct but will not work with my java. It just returns false.
String word = " [00:00:00.000] ";
Pattern pattern = Pattern.compile("^\\s[[0-9:.]*]\\s");
Matcher matcher = pattern.matcher(word);
if(matcher.matches()){
//Do Stuff
else
//Do other Stuff
\\s*\\[[0-9:.]*\\]\\s*
Use this.You dont need ^.escape [].See demo.
https://regex101.com/r/eX9gK2/11
If you want timestamps use
\\s*\\[([0-9:.]*)\\]\\s*
and capture the group 1
\\[\\d{2}:\\d{2}:\\d{2}\\.\\d{3}\\] would have been the right answerTry with:
^\\s\\[[0-9:.]*]\\s
You regex doesn't work because you did't escape first [ character, so it is treated as another character class. You can get timestamp by closing it into group: ([0-9:.]*), but also, if your timestamp always look like this, you can get separate time values with:
^\\s\\[(\\d+):(\\d+):(\\d+)\\.(\\d+)*]\\s
it will give you:
test it in Java:
public static void main(String args[]){
String word = " [00:00:00.000] ";
Pattern pattern = Pattern.compile("^\\s\\[(\\d+):(\\d+):(\\d+)\\.(\\d+)*]\\s");
Matcher matcher = pattern.matcher(word);
matcher.find();
System.out.println(matcher.group(1) + ":" + matcher.group(2) + ":" + matcher.group(3) + "." + matcher.group(4));
}
package test;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import static org.junit.Assert.assertTrue;
import org.junit.Test;
public class RegexTest {
@Test
public void assert_pattern_found() {
final String word = " [00:00:00.000] ";
final Pattern pattern = Pattern.compile("^\\s\\[[0-9:.]*\\]\\s");
final Matcher matcher = pattern.matcher(word);
assertTrue(matcher.matches());
}
}
[like\[and the last]like\]. The reason is that the angle brackets are a special character in regular expressions. So the regex checker is wrong. So, I think this would also have caused issues in other programming languages. (Note, in java you will need to escape twice, (\\[and\\])