Parse error: Implode function

<?php // highlighting

if(is_array($filter)){
 $filter = '`'.implode('|',$filter).'`';
}

<?php // highlighting
$resultsArray = array('parents'=>'3'
                      , 'tpl'=>'TourListingRowTPL'
                      , 'filter'=>preg_replace('/`/','',$filter)
                      , 'paginate'=>'1'
                      , 'display'=>'all'
                      , 'orderBy'=>$order
                      , 'noResults'=>'#####');

<?php
  $resultsArray = array(
   'parents'=>'3',
   'tpl'=>'TourListingRowTPL',
   'filter'=>'duration,100,4',
   'display'=>'all',
   'orderBy'=>'duration DESC',
   'noResults'=>'#####');
  $result = $modx->runSnippet('Ditto', $resultsArray);

<?php
   'filter'=>'duration,100,4|searchDests,19,7'
   'filter'=>'searchDests,19,7|duration,100,4'
   'filter'=>'searchDests,19,7'