PHP: Undefined offset in for loop - php

Question

While making a photo gallery I encountered a problem. With every photo I try to show how many comments it has, however if a photo has 0 comments it will give me an 'undefined offset' error. I have no idea what I am doing wrong because it does show that there are 0 comments.
This is the code of what is relevant to the problem:
(The problem occurres in the line: if($reacties[$i]==0){)
if((isset($_GET['vanafFoto'])) AND (intval($_GET['vanafFoto']>=0)) AND (intval($_GET['vanafFoto'] < $countFotos))){
$begin = intval($_GET['vanafFoto']);
if(($begin + $aantalFotos) <= $countFotos){
$eind = ($begin + $aantalFotos);
} // end if
else {
$eind = $countFotos;
} // end else
} // end if
else {
$begin = 0;
$eind = $aantalFotos;
} // end else
$countFotos = count($fotoArray);
// path naar echte foto
} // end else
echo "<table border='0' cellpadding='0' cellspacing='2'><tr><td ><b>" . $pathspatie . "</b> <small>(" . $count . ")</small>
<br><br><center><small>Pictures " . ($begin + 1) . " - " . $eind . "</small></center></td></tr></table>";
if(($begin - $aantalFotos) >= 0){
$navigation = "<a href='" . $_SERVER['PHP_SELF'] . "?page=album&boek=" . $originalPath . "&vanafFoto=" . ($begin - $aantalFotos) . "'><</a> " . $navigation;
} // end if
if(($begin + $aantalFotos) < $count){
$navigation .= " <a href='" . $_SERVER['PHP_SELF'] . "?page=album&boek=" . $originalPath . "&vanafFoto=" . ($begin + $aantalFotos) . "'>></a>";
} // end if
echo $navigation . "<br><br>";
echo "</td></tr><tr>";
$fotonr = 1;
for($i=$begin; $i < $eind; $i++){
$thumb = str_replace($path2, $thumbPath, $fotoArray[$i]);
echo "<td align='center'><a href='" . $_SERVER['PHP_SELF'] . "?page=album&boek=" . $originalPath . "&fotoID=" . $i . "'><img border='0' src='" . $thumb . "' height='100'><br>";
echo "<small>reacties (";
if($reacties[$i]==0){ // error occurres here.
echo "0";
} // end if
else {
echo $reacties[$i];
} // end else
echo ")</small>";
echo "</a></td>";
$fotonr++;
if($fotonr == ($clm + 1)){
echo "</tr>\n<tr>";
$fotonr = 1;
} // end if
} // end for
If anyone can see what the problem is it would be great!

Answer 1

I did not understand you exact goal but maybe it is better to write one more check:
if(!isset($reacties[$i]) || $reacties[$i]==0){
echo "0";
}