RegEx & PHP 多个变量

Question

我第一次忙于正则表达式PHP。

我想做一个车牌检查器，在字母和数字之间加上'-'。现在一切正常，但唯一的问题是对于每个字符串我都会得到另一个变量。

喜欢：对于 999TB2，我得到 $1 $2 $3，但第二个字符串 9999XX 将是 $4 $5 $6。是否有可能获得第二个字符串 $1 $2 $3?

<?php
$re = '/^(\d{3})([A-Z]{2})(\d{1})|(\d{2})(\d{2})([A-Z]{2})$/';
$str = '9999XX'; //(Will be later connected to database)
$subst = '-- --';

$result = preg_replace($re, $subst, $str, 1);
echo "The result of the substitution is ".$result;

?>

亲切的问候

Answer 1

您可以使用分支重置组 (?| 并且您可以从模式中省略 {1}。

^(?|(\d{3})([A-Z]{2})(\d)|(\d{2})(\d{2})([A-Z]{2}))$

看到一个regex demo and a PHP demo。

示例代码

$strings = [
    "999TB2",
    "9999XX"
];

$re = '/^(?|(\d{3})([A-Z]{2})(\d)|(\d{2})(\d{2})([A-Z]{2}))$/';

foreach ($strings as $str) {
    echo preg_replace($re, '--', $str) . PHP_EOL;
}

输出

999-TB-2
99-99-XX

RegEx & PHP 多个变量

RegEx & PHP multiple variabels

php

regex