Well, something is to be said for approaching a problem from different points of view and uncovering new truths. So I'll give it a try.

The solution wasn't as smooth as I'd hope, apparently -0.0 == 0.

my $sign = "";
my $number = -0.000001;

my $example = sprintf("%.5f", $number);
#$example = $number; #uncomment this, to remove the initial rounding

print "A. Started with : $example \n";
if ($example < 0) {
    $example = -$example;    
    $sign = "-";

    print "B. Less than zero: changed to  $example \n";
}

print "C. the number is $example \n";
if ($example == 0 )
{
    print "D1. the number ($example) is equal to zero, removing the si
+gn.\n";
    $example *= -1; #(couldn't hurt, it's zero)
    print "D2. the number ($example) is equal to zero, removing the si
+gn.\n";
    $sign = '';
}

print "E. proceeding to sprint $example with sign $sign .\n";
$tret = sprintf("rounded float: %s%7.5f : unrounded %7.5f", $sign, $ex
+ample, $number);
print "$tret \n";
[download]

A. Started with : -0.00000 
C. the number is -0.00000 
D1. the number (-0.00000) is equal to zero, removing the sign.
D2. the number (0) is equal to zero, removing the sign.
E. proceeding to sprint 0 with sign  .
rounded float: 0.00000 : unrounded -0.00000 

rgiskard:

Clearly I was wrong. ;^)

But I have another idea--and it's a bit shorter than the last one!

$example = abs($example) if abs($example) < 0.00001;
[download]

I hope this one is better than the last one...

Unfortunately, I've gotta pick up my son from school, so this one too is untested. ;^(

...roboticus

Ironically, "-0.0" == 0 BUT triggers true in an ||... using that, however you CAN do...

$num = '-0.0000009';
$num = sprintf("%7.5f",$num);
$num = $num == 0 ? '0.00000' : $num;
print "$num\n";
[download]

I was hoping || would work, cuz then you could do

$num = sprintf("%7.5f",$num) || '0.00000';
[download]

but alas, no. The following works...

$num = sprintf("%7.5f",$num)+0 || '0.00000';
[download]

but you lose all trailing zeros, which works if you only want to round, but not for formatting, so probably doesn't help.

                - Ant
                - Some of my best work - (1 2 3)