Remove duplicate WordPress post meta

gistfile1.php

<?php

require_once('../../../wp-load.php'); //File was temporarily placed in the theme

define( 'WP_DEBUG_DISPLAY', true );
ini_set( 'display_errors', true );
$allposts = get_posts('numberposts=-1&post_type=guide&post_status=any'); //Post query
$keys = array('address', 'address2', 'city', 'state', 'zip'); //Add post meta keys here
foreach ( $keys as $key ) {
    foreach( $allposts as $postinfo) {
        // Fetch array of custom field values
        $postmeta = get_post_meta($postinfo->ID, $key);

        //print_r($postinfo);

        if (!empty($postmeta) ) {
            // Delete the custom field for this post (all occurrences)
            delete_post_meta($postinfo->ID, $key);

            // Insert one and only one custom field
            update_post_meta($postinfo->ID, $key, $postmeta[0]);
        }
    }
}

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