Just how tied to the hash are you? Assuming you have a function call such as: myfunc($ts, $interval), then something like the following might also be worth considering: 

sub myfunc {
    my ($ts, $interval) = @_;
    my $minute;
    #
    # Somehow get $minute from $ts, 
    #   using the method of your choice.
    #
    #   Ex., using the method in the OP...
    $minute = substr($ts, 10, 2);
    return $interval * int($minute / $interval);
}

[download]
as it appears to provide the same results you seek, but perhaps with a little less brain-damage....

Hope that helps.

In reply to Re: Round time to nearest 15 or 30 minutes by atcroft
in thread Round time to nearest 15 or 30 minutes by jesuashok

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