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Re^3: Understanding transformation sorts (ST, GRT), the details

by merlyn (Sage)
on May 18, 2005 at 17:08 UTC ( #458311=note: print w/replies, xml ) Need Help??


in reply to Re^2: Understanding transformation sorts (ST, GRT), the details
in thread Understanding transformation sorts (ST, GRT), the details

(split(/\./,$_,3))[1] =~ /^(\d+)([A-Za-z]+)(\d+)$/; [$_, $3, $months{$2}, sprintf("%02d", $1) ]
I guess this is my day to point out bad uses of $1 in the first stage of a ST. {grin}

So, to repeat what I said there...

You are using $1, $2, $3 without testing the success of the match. This means that you might possibly be getting the previous round's data, resulting in duplicated output. What you should be doing instead is skipping over the erroneous entries, or perhaps dieing. Just to be different from the previous node, let's do the die thing:

(split(/\./,$_,3))[1] =~ /^(\d+)([A-Za-z]+)(\d+)$/ or die "improperly + formed data: $_"; [$_, $3, $months{$2}, sprintf("%02d", $1) ]

-- Randal L. Schwartz, Perl hacker
Be sure to read my standard disclaimer if this is a reply.

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