writing multiple arrays in one remains empty when only one array to add

I load a xml-file which contains several arrays.

$array0 = (.......)
$array1 = (.......)
...
$arrayN = (.......)

In my HTML-part I have a DIV to display each array. To do it write all arrays in one masterarray:

for ( $i = 0; $i < 1; $i++) $masterArray[] = ${'array'.$i};

and can access each array

$Titel = $masterArray[0] [$i] [$kat] [0] ["TitelD"];

This works if I have more than one array in my xml-File. If I have only one the masterarray rests empty. Why that? If I copy a second in the xml-File it works... (with displaying the second!)

What can I do to get only one array in the masterarray?