The RegEx ^([0-9])+$ supports numbers and spaces. However, I want it to support empty lines too. How?
views:
55answers:
5
A:
^([0-9])*$ Change + to *
Btw your code does not support spaces for adding spaces regex should have [0-9\s]
Hasan Khan
2010-08-13 11:34:51
+2
A:
Use this instead:
^([0-9])*$
or, more simply:
^\d*$
\d means any digit (0-9). + means one or more matches. * means zero or more matches.
cletus
2010-08-13 11:35:05
\d is Perl specific and won't work if OP is using e.g. grep
Jonathan Maddison
2010-08-13 11:42:21
@Jonathon `\d` is most certainly *not* Perl specific. I can't claim universal functionality but Perl only? Not a chance. Java, C+, PHP and Python all allow it, just off the top of my head.
cletus
2010-08-13 11:43:05
as cletus points out, most programming languages use some form of perl-like notation for digits, spaces, etc. The equivalent in POSIX regexes would be [[:digit:]] I suppose.
wds
2010-08-13 12:10:43
+1
A:
Also, note that in your original (and the recommendations here), you are making a tagged group of just the first digit. If you want the entire number in the capture, you need the + (or *) inside the perens:
^([0-9]*)$
On the other hand, if you don't need a capture, you don't need the perens at all:
^[0-9]*$
James Curran
2010-08-13 11:39:01
A:
By empty line don't you mean a line with a carriage return? Wouldn't that simply be ^(\d*\s*\n)$?
stocherilac
2010-08-13 11:47:45