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Re: Finding gaps in date ranges

by perlmonkey (Hermit)
on May 11, 2001 at 05:47 UTC ( #79623=note: print w/replies, xml ) Need Help??

in reply to Finding gaps in date ranges

Instead of trying to find out what you are missing, it is a lot easier (and faster) to just exclude what you have.
sub find_gaps { my $dates = shift; my @dates = sort{ $a->[0] <=> $b->[0] || $a->[1] <=> $b->[1] } map{[substr($_, 0, 4), substr($_, 5)]} keys %$dates; my( $minY,$minM,$maxY,$maxM ) = (@{$dates[0]}, @{$dates[-1]}); my @gaps; for my $y ($minY .. $maxY) { exists $dates->{"$y-$_"} ? next : push @gaps, "$y-$_" for ($minY == $y ? $minM : 1) .. ($maxY == $y ? $maxM : 12); } return \@gaps; }
This code sorts to finds the min and max of the date range, then loops over the entire range in order looking to see if we have that date already. If we dont have the date then keep it to return.

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[atcroft]: abner: Do you mean something like SELECT `foo`, `bar` FROM `table_name' WHERE (( `foo` = "asdf" ) OR ( `bar` = 'asdw' )); Or something else?
[abner]: yes. i am familiar with mysql but ignorant about how to get around the fact that placeholders can only represent single scalar values.
[abner]: my $sth = $dbh->prepare(' SELECT * FROM charge WHERE cpt = ?') or die "Couldn't prepare statement: " . $dbh->errstr;

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