in reply to Re: Round down to '.5' or '.0'
in thread Round down to '.5' or '.0'

Conversely, is there another trick to do the same but round up?

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Re^3: Round down to '.5' or '.0'
by ikegami (Patriarch) on Oct 24, 2007 at 20:10 UTC 
    use POSIX qw( ceil );
my $rounded = ceil($num*2)/2;

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    Update: Oops, the above didn't work for negative numbers. 

    use POSIX qw( ceil );
my $rounded = ($num>=0 ? +1 : -1) * ceil(abs($num)*2)/2;

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    or 

    use POSIX qw( ceil floor );
my $rounded = ($num >= 0
   ? ceil($num*2)/2
   : floor($num*2)/2
);

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