Re: Regular Expressions Matching with Perl

Regexen should be a short as possible, but no shorter.

my( $file ) = /[[:hexdigit:]]{8}\s+(.*)$/;
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Re^2: Regular Expressions Matching with Perl by ikegami (Patriarch) on Apr 20, 2005 at 17:49 UTC
Too short. That fails if the file size is 10,000,000 bytes or more. `my ($file) = $line =~ /:.{15}(.*)/;` would be minimal.	[reply] [d/l]
Re^3: Regular Expressions Matching with Perl by Fletch (Bishop) on Apr 20, 2005 at 18:21 UTC
Erm, it's matching against the 8 hex digits of the CRC-32. How is that affected by the file size? Granted on further examination of `unzip -v` output it should be anchored off the date as well. `/:\d\d\s\s[[:hexdigit:]]{8}\s\s(.*)$/` [download]	[reply] [d/l]
Re^4: Regular Expressions Matching with Perl by ikegami (Patriarch) on Apr 20, 2005 at 18:39 UTC
Erm, it's matching against the 8 hex digits of the CRC-32. How is that affected by the file size? If the file size is 10000000 bytes or higher, your original regexp will not match against the 8 digits of the CRC-32 as you say. Instead, it will match against the 8 digits of the file size, because they come earlier. That's why I used the date as the anchor.	[reply]