[Custom Fields] Howto hide custom fields when they are empty?

Hey,

I did create 4 custom fields:

Meters
Time
Pulsavg
GarminConnectLink

The idea is when I post in the category “lob” then I will use that category as a traing log.

Based on my date: meter and time I did made a script that calculates the km per hour and minutes per km.

Then problem is I dont know howto not show the field when they are empty…

If you see: https://www.liljefred.dk/frederik/lob/9km-i-traedemollen/ it looks great:

* Meters: 9000
* Time: 00:53:44
* Km/hour: 10.05
* Min/km: 05:58 minutes
* Puls average: 172
* Garmin Connect Link: https://www.test.dk

But at https://www.liljefred.dk/familien-liljefred/fam-liljefred-goes-www/ it doesnt look good as I didnt give that post any values as the post is not meant as a training log:

Warning: Division by zero in /home/frold/liljefred.dk/wp-content/themes/mystique/single.php on line 53

Warning: Division by zero in /home/frold/liljefred.dk/wp-content/themes/mystique/single.php on line 57

* Meters:
* Time:
* Km/hour: 0
* Min/km: 00:00 minutes
* Puls average:
* Garmin Connect Link:

The code I use in single.php is:

<?php
// Running script by frold @ liljefred.dk
//Get the running time
	$hms = get_post_meta($post->ID, "Time", $single = true);
//Get the distance
	$meters = get_post_meta($post->ID, "Meters", $single = true);
//Get the Garmin Connect Link
	$url = get_post_meta($post->ID, "GarminConnectLink", $single = true);
//Get pulsavg.
	$pulsavg = get_post_meta($post->ID, "Pulsavg", $single = true);

//Let us convert the total running time into seconds
	function hms2sec ($hms) {
	list($h, $m, $s) = explode (":", $hms);
	$seconds = 0;
	$seconds += (intval($h) * 3600);
	$seconds += (intval($m) * 60);
	$seconds += (intval($s));
	return $seconds;
}
//Call the function
	$seconds = hms2sec($hms);

//Calculate the avg running speed in km/hour
	$km_per_hour = (($meters/1000) / ($seconds/3600));
	$km_per_hour_round = round($km_per_hour, 2);

//Calculate number of minutes per km
	$min_per_km = ($seconds) / ($meters/1000);
	$minutes = floor($min_per_km/60);
	$secondsleft = $min_per_km%60;
	if($minutes<10)
		$minutes = "0" . $minutes;
	if($secondsleft<10)
		$secondsleft = "0" . $secondsleft;

//Print it all
	echo "<ul class='post-meta'>";
	echo "<li><span class='post-meta-key'>Meters:</span> $meters</li>";
	echo "<li><span class='post-meta-key'>Time:</span> $hms</li>";
	echo "<li><span class='post-meta-key'>Km/hour:</span> $km_per_hour_round</li>";
	echo "<li><span class='post-meta-key'>Min/km:</span> $minutes:$secondsleft minutes</li>";
	echo "<li><span class='post-meta-key'>Puls average:</span> $pulsavg</li>";
	echo "<li><span class='post-meta-key'>Garmin Connect Link:</span> <a href='$url' target='_blank'>$url</a></li>";
	echo "</ul>";
//EoM
?>

I hope you can help….