Gravity forms field array/string to array

disarray.php

<?php

$string = $gv_entry->entry['30'];

// Remove brackets.
$string = trim( $string, '[]' );

$post_ids = array_map(
  function( $string_id ) {
    // Remove quotes around IDs.
    return trim( $string_id, '"' );
  },
   explode( ',', $string )
);