Snippet to filter duplicate TV values

<option value="[[+country]]">[[+country]]</option>

 $children = $modx->resource->getMany('Children');

<?php 
$children = $modx->resource->getMany('Children');

if (!$children) { return false; }

// Check if there is a tpl set, if not return an error
$tpl = $modx->getOption('tpl', $scriptProperties, '');

if (!$tpl) { return 'No template given.'; }

foreach($children as $child) {
   	$out = array(
      'country' => $child->getTVValue('country')
      );
    // ... and adding it to the output as placeholders in the chunk
    $o .= $modx->getChunk($tpl, $out);
}
return $o;

$property_types = array();
foreach($search_results_unique as $filter_result){
    if ( in_array($filter_result['property_type'], $property_types) ) {
        continue;
    }
    $property_types[] = $filter_result['property_type'];
    echo $filter_result['property_type'];
}

<?php 

$children = $modx->resource->getMany('Children');

if (!$children) { return false; }
// Check if there is a tpl set, if not return an error
$tpl = $modx->getOption('tpl', $scriptProperties, '');
if (!$tpl) { return 'No template given.'; }

$filter_countries = array();
foreach($children as $child) {
    $country = $child->getTVValue('country');
    if ( in_array($country, $filter_countries) ) {
        continue;
    }
    $filter_countries[] = $country;
    $out = array(
        'country' => $country
    );
    $o .= $modx->getChunk($tpl, $out);
}
return $o;

$o = '';
$tvId = 23; /* ID of the country TV */
$countries = array();
$result = array();

$docIds = $modx->getChildIds(38);
if (empty($docIds) { 
    return false; 
}
// Check if there is a tpl set, if not return an error
$tpl = $modx->getOption('tpl', $scriptProperties, '');
if (!$tpl) { return 'No template given.'; }


$c = $modx->newQuery('modTemplateVarResource');
$c->select(array('value'));
$c->distinct(true);
$c->sortby('value');  /* (optional) */
$c->where(
    array(
        'tmplvarid' => $tvId,
        'contentid:IN' => $docIds,
        'value:!=' => '',
    )
);

if ($c->prepare() && $c->stmt->execute()) {
    $result = $c->stmt->fetchAll(PDO::FETCH_ASSOC);
}
$countries = array_map('current', $result);

foreach($countries as $country) {
    $o .= $modx->getChunk($tpl, array('country' => $country));
}

$c->select(array('value'));

$c->select(array('contentid'));