RegEx - contains numbers but no letters

[Jerry Lee]

I tried for an hour and could figure it out. I could find a way around, but I'd like to know the answer.

I am reading a file and would like to remove lines as follows:
00:02:21,365 --> 00:02:24,027

So, please give a Java regular expression that will pick up a line that contains numbers, but it doesn't contain any letters. Therefore:

1) 00:02:21,365 --> 00:02:24,027 (Yes)
2) (an empty line) (No - because it doesn't have numbers)
3) whatever123 (No - because it has letters)

Thanks.

[fred rosenberger]

can you show us some of the things you've tried?

[Jerry Lee]

I tried this one it doesn't work.
[0-9&&[^a-zA-Z]]

After reading this page, I know why it doesn't work now:
http://java.sun.com/docs/books/tutorial/essential/regex/char_classes.html

Regular Expression Test Page:
http://www.fileformat.info/tool/regex.htm

[Campbell Ritchie]

Have you found the escape sequences which match digits? You should find them in the Java Tutorial link you posted. I think you want something like \d, but in a String literal you have to escape the \ like this "\\d".

[Alan Moore]

Originally posted by Jerry Lee:
I tried this one it doesn't work.
[0-9&&[^a-zA-Z]]

That regex matches one character that is a digit and isn't a letter. You need a regex that matches a whole line, and you need to do the two tests separately. One regex for a line of characters other than letters would be

^[^A-Za-z]+$

...and for a line that contains a digit,

^.*[0-9].*$

You don't need to call matches() twice though, because you can state one of the requirements as a lookahead:

^(?=[^A-Za-z]+$).*[0-9].*$

Finally, if you use the matches() method, you don't need the '^' and '$' anchors at either end of the regex, but you do need the '$' in the lookahead, to make sure it checks the whole line.

if (line.matches("(?=[^A-Za-z]+$).*[0-9].*"))
{
  // remove it
}

By the way, here's a site with a better regex tutorial:

http://www.regular-expressions.info/
[ May 28, 2008: Message edited by: Alan Moore ]

[Jerry Lee]

Thank you very much for the detailed info. This is really helpful.