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Re: Re: Re: Finding missing elements in a sequence (code)

by clemburg (Curate)
on Nov 06, 2001 at 22:13 UTC ( #123647=note: print w/ replies, xml ) Need Help??


in reply to Re: Re: Finding missing elements in a sequence (code)
in thread Finding missing elements in a sequence (code)

The first numeric sort is 'numerifying' the strings and stripping the leading zeroes which messes up the rest of the routine.

I am not if that is right, at least not in the simple sense of what you say. See:

sub find_holes { my @list = @{ shift() }; @list = sort { $a <=> $b } @list; my $low = $list[0]; my $high = $list[-1]; my %isthere = map { $_ => 0 } ($low..$high); print "@{[sort keys %isthere]}\n\n"; print "@list\n\n"; $isthere{$_} = "yes" for map {$_+0} @list; my @vacancies = grep { not $isthere{$_} } sort keys %isthere; return \@vacancies; } my @issues = @{ [ '00001', '00002', '00003', '00004', # '00005', '00006', '00007', '00008', '00009', #... ] }; print join("\n", @{ find_holes( \@issues ) });

Prints:

d:\tmp\try>perl try.pl perl try.pl 1 2 3 4 5 6 7 8 9 00001 00002 00003 00004 00006 00007 00008 00009 5

What the sort probably does is to fill the number entry in the glob of the entries of @list. But why does the ".." operator use the number slot, while the hash access code and print use the string slot?

Christian Lemburg
Brainbench MVP for Perl
http://www.brainbench.com


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