[Omaha.pm] Count occurrences of the value of an attribute in XML
Andy Lester
andy at petdance.com
Tue May 29 19:04:51 PDT 2007
On May 29, 2007, at 7:39 PM, Jay Hannah wrote:
> $ perl -lne '/rt="(\w+)"/; print $1' RevData.DALMAN.20070529.xml |
> uniq
Actually, this is wrong. You cannot rely on the value of $1 if the
m// did not match. Your "optimization" to /rt.../ && print $1 is
necessary or else it is wrong.
See http://perl101.org/regexes.html "Don't use capture variables
without checking that the match succeeded."
xoxo,
Andy
--
Andy Lester => andy at petdance.com => www.petdance.com => AIM:petdance
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