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Re^3: Strange regex to test for newlines: /.*\z/

by xicheng (Sexton)
on May 22, 2007 at 18:17 UTC ( #616824=note: print w/ replies, xml ) Need Help??


in reply to Re^2: Strange regex to test for newlines: /.*\z/
in thread Strange regex to test for newlines: /.*\z/

$ and \Z work pretty much the same in normal mode, both match the end of search string or before a string-ending newline. the difference between them lies in the multiline mode when you issue an 'm' modifier.

\z means the real end of string even after the string-ending newline.

If you use an 's' modifier, then things become more different but that's mainly coz of the '.' which changes its behaviors, not the three end-of-string anchors..

check the following snippets:

perl -e 'print "match\n" if "foo\n" =~ /.+$/' # ok # perl -e 'print "match\n" if "foo\n" =~ /.+\z/' perl -e 'print "match\n" if "foo\n" =~ /.+\Z/' # ok # perl -e 'print "match\n" if "foo\n\n\n" =~ /.+\Z/' perl -e 'print "match\n" if "foo\n\n\n" =~ /.+\z/' perl -e 'print "match\n" if "foo\n\n\n" =~ /.+$/' perl -e 'print "match\n" if "foo\n\n\n" =~ /.+$/m' # ok # perl -e 'print "match\n" if "foo\n\n\n" =~ /.+\z/m' perl -e 'print "match\n" if "foo\n\n\n" =~ /.+\Z/m' perl -e 'print "match\n" if "foo\n\n\n" =~ /.+\Z/s' # ok # perl -e 'print "match\n" if "foo\n\n\n" =~ /.+\z/s' # ok # perl -e 'print "match\n" if "foo\n\n\n" =~ /.+$/s' # ok #
BTW. When comparing between \z, \Z and $, it's probably better to avoid using .* or .? quanifiers the ways in your examples.

BTW. my previous statement about \Z had some error and I have updated that post.

Regards,
Xicheng


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