问在搜索查询中，花括号之间的数字是多少？

EN

/**
 * Adds a placeholder escape string, to escape anything that resembles a printf() placeholder.
 *
 * @since 4.8.3
 *
 * @param string $query The query to escape.
 * @return string The query with the placeholder escape string inserted where necessary.
 */
public function add_placeholder_escape( $query ) {
    /*
     * To prevent returning anything that even vaguely resembles a placeholder,
     * we clobber every % we can find.
     */
    return str_replace( '%', $this->placeholder_escape(), $query );
}

/**
 * Removes the placeholder escape strings from a query.
 *
 * @since 4.8.3
 *
 * @param string $query The query from which the placeholder will be removed.
 * @return string The query with the placeholder removed.
 */
public function remove_placeholder_escape( $query ) {
    return str_replace( $this->placeholder_escape(), '%', $query );
}