如何修复preg_match（）未知修饰符'？在localeconv（）中

Question

问题出在 'decimal_point' => string '/'但是没有人有好的解决方案吗？错误：  preg_match() unknown modifier '?'功能 ：     * @param   string  $str    input string     * @return  boolean     */    public static function numeric($str)    {        // Get the decimal point for the current locale        list($decimal) = array_values(localeconv());        // A lookahead is used to make sure the string contains at least one digit (before or after the decimal point)         return (bool) preg_match('/^-?+(?=.*[0-9])[09]*+'.preg_quote($decimal).'?+[0-9]*+$/D', (string) $str); }这是localeconv（）dump：array (size=18)  'decimal_point' => string '/' (length=1)  'thousands_sep' => string ',' (length=1)  'int_curr_symbol' => string 'IRR' (length=3)  'currency_symbol' => string 'ريال' (length=8)  'mon_decimal_point' => string '/' (length=1)  'mon_thousands_sep' => string ',' (length=1)  'positive_sign' => string '' (length=0)  'negative_sign' => string '-' (length=1)  'int_frac_digits' => int 2  'frac_digits' => int 2  'p_cs_precedes' => int 0  'p_sep_by_space' => int 0  'n_cs_precedes' => int 0  'n_sep_by_space' => int 0  'p_sign_posn' => int 3  'n_sign_posn' => int 3  'grouping' =>     array (size=1)      0 => int 3  'mon_grouping' =>     array (size=1)      0 => int 3