php - conditionally change array used in foreach loop -

i want conditionally change array looped though foreach loop , send var in

url = domain.com/myphppage.php?myarray=$array1 

script has 2 arrays. $_get used var url , foreach loop uses 1 of 2 arrays output array content on page.

    <?php      $array1 = array(1,2,3,4)     $array2 = array(5,6,7,8)     ?>      <?php      $arrayused = $_get['myarray'];     echo $arrayused;      ?>      <?php foreach($arrayused $item): ?>      html code show loop values     <?php endforeach; ?> 

the var passed url shown on page output echo $arrayused.

i expecting $arrayused variable picked foreach , looped through whichever of 2 arrays in variable.

however, doesn't pick variable , not go foreach loop. if hardcode either of 2 array names foreach statement, foreach loop works fine.

why doesn't foreach statement appear 'recognize' variable retrieved url? prints on page before loop available?

if understand correctly - $arrayused string can 'array1' or 'array2'.

than should add additional $ beggining of variable (variable variables).

here code sample:

<?php $array1 = array(1,2,3,4); $array2 = array(5,6,7,8); ?>  <?php $arrayused = 'array1'; echo $arrayused; ?>  <?php foreach($$arrayused $item): ?>     html code show loop values <?php endforeach; ?>