 |
 | Home | Contact Us | FAQ | Search & Site Map | Link to Us |
 | Sign In | Join | Other 45 Sites in Network |
Java Forum / General / April 2006Stupid regex problem
Hi, Can someone explain why Pattern.matches(".*", "123\r\n"); yields false? (Removing \r\n makes it return true) Thanks, Koos  Signature43rd Law of Computing: Anything that can go wr fortune: Segmentation violation -- Core dumped > Can someone explain why > > Pattern.matches(".*", "123\r\n"); > > yields false? (Removing \r\n makes it return true) Did you read what the Pattern class documentation says matching line terminators? /gordon Signature[ do not email me copies of your followups ] g o r d o n + n e w s @ b a l d e r 1 3 . s e > Did you read what the Pattern class documentation says matching line > terminators? ...says *about* matching line terminators. /gordon Signature[ do not email me copies of your followups ] g o r d o n + n e w s @ b a l d e r 1 3 . s e >> Can someone explain why >> [quoted text clipped - 4 lines] > Did you read what the Pattern class documentation says matching line > terminators? Aah, thanks Gordon. My Perl background stood in the way. In Perl the EOL would be irrelevant. Thanks again. Koos - Using (?s:.) now Signature43rd Law of Computing: Anything that can go wr fortune: Segmentation violation -- Core dumped >Aah, thanks Gordon. My Perl background stood in the way. >In Perl the EOL would be irrelevant. It depends on the meaning of »the EOL would be irrelevant«. For example, in Perl 5.8.3, print "12345" =~ /^.*$/ ? 1 : 0; print "123\r4\n5" =~ /^.*$/ ? 1 : 0; prints 10 . >>In Perl the EOL would be irrelevant. > > It depends on the meaning of »the EOL would be irrelevant«. No it does not. In the described problem the EOL is simply irrelevant. print "12345" =~ /^.*$/ ? 1 : 0; print "123\r\n" =~ /^.*$/ ? 1 : 0; print "12345 " =~ /./ ? 1 : 0; # or even this print "123\r\n" =~ /./ ? 1 : 0; # prints 1111 Cheers, Koos Signature43rd Law of Computing: Anything that can go wr fortune: Segmentation violation -- Core dumped >>>In Perl the EOL would be irrelevant. >> It depends on the meaning of »the EOL would be irrelevant«. [quoted text clipped - 4 lines] >print "123\r\n" =~ /./ ? 1 : 0; # >prints 1111 Insofar you are right. But the following example for Perl 5.8.3 shows that "\r\n" is not always matched by the ".*": print "12345" =~ /^.*$/ ? 1 : 0; print "123\r\n5" =~ /^.*$/ ? 1 : 0; It prints »10« here. It seems as if there was a special rule for a trailing "\r\n", that does not apply anymore when "\r\n" appears in the middle of a text. What I sometimes use to match it, is: print "12345" =~ /^[^\001]*$/ ? 1 : 0; print "123\r\n5" =~ /^[^\001]*$/ ? 1 : 0; This could be used in Java as well, I assume. >Can someone explain why > > Pattern.matches(".*", "123\r\n"); see http://mindprod.com/jgloss/regex.html#QUOTING SignatureCanadian Mind Products, Roedy Green. http://mindprod.com Java custom programming, consulting and coaching. >> Pattern.matches(".*", "123\r\n"); > > see http://mindprod.com/jgloss/regex.html#QUOTING If I'm not mistaken that's about the regex itself and not the search string. Koos Signature43rd Law of Computing: Anything that can go wr fortune: Segmentation violation -- Core dumped >> see http://mindprod.com/jgloss/regex.html#QUOTING > >If I'm not mistaken that's about the regex itself and not the search >string. The regex IS the search string. The complexity comes from quoting for two logical levels, the regex and Java string literals, both of which use \ The entry covers both. SignatureCanadian Mind Products, Roedy Green. http://mindprod.com Java custom programming, consulting and coaching. Free MagazinesGet these publications absolutely FREE for up to 12 months. There are no hidden fees and no obligation. Simply choose a title, complete the application form and submit it. Read more ...
|
Reply to this Message
|
 Sign In
 Join
 My Latest Posts My Monitored Threads My Blog My Photo Gallery My Profile My Homepage Start New Thread Enable EMail Alerts Rate this Thread
|
©2008 Advenet LLC Privacy Policy - Terms of Use
This website includes both content owned or controlled by Advenet as well as content owned or controlled by third parties.