Re: Round time to nearest 15 or 30 minutes

[atcroft]

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);
}

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

Hope that helps.

[jesuashok]

Hi

Thanks a lot.
definitely I have to improve my logical Ideas.
That is working fine as expected.

[DrHyde]

If you want the nearest 15 minute boundary, then the code is wrong. It will give you the previous 15 minute boundary.

You need to:

• add $interval/2 minutes to the time;
• subtract the remainder you'd get when dividing by $interval minutes.

Note that the modulus operator % only works with integers. In practice, you can probably ignore the fraction of a minute that gets thrown away. If you can't, then you'll need to write your own remainder function.

[bill_mcgonigle]

Ah, this was very helpful, thanks. Not being too clever in these matters, I didn't quite understand the above, but it got me close enough to experiment successfully (though I don't quite get the second bullet item). In my case I was after an offset to add to a unixtime, so that's how the code is oriented.

for (my $i = 0; $i < 60; $i++) {

    my $offset = getOffsetToNearestInterval($i,15);
    print "$i: " . ($i + $offset) . ' (' . $offset . ')' . "\n";

}

sub getOffsetToNearestInterval {

    my $number = shift;
    my $interval = shift;

    my $nearest_interval = ( $interval * int( ($number + ($interval/2)
+ ) / $interval) );
    my $offset_to_interval = $nearest_interval - $number;

    return $offset_to_interval;
}

Hope this helps the next guy stumbling on this thread.