PERL Beginners - how to search for intervals in multiple columns?

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how to search for intervals in multiple columns?

Martin A. Hansen

2004-10-28, 3:57 pm

hi

i have a dataset consisting of an array of arrays.

$data = [
[q_beg1, q_end1, s_beg1, s_end1]
[q_beg2, q_end2, s_beg2, s_end2]
[q_beg3, q_end3, s_beg3, s_end3]
...
]

q_beg, q_end, s_beg, s_end are all integers.

now, i would like to find all rows where q_beg and q_end are within one
interval (int1_beg, int1_end) while s_beg and s_end are within another
interval (int2_beg, int2_end).

this can be done with grep:

grep {$_->[0] < int1_beg and $_->[1] > int1_end and
$_->[2] < int2_beg and $_->[3] > int2_end} @$data;

however, this is too slow for my purpose. so how to speed up such
selection?

the query would be simple enough in a relational database, however i
want to avoid using a database using tables on disk.

i should think this was a pretty generic problem.

ideas are most welcome !

best regards

martin

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