一个正则表达式的疑问，麻烦帮忙下，谢谢！

[MUGOER]

一段内容如下:

A100B200C300D400AA100BB3554CC45648DD4563


单独匹配A100 或 AA100

(A\d+)虽然可以匹配到A100却也可以匹配到AA100


(A\d+) --匹配出来了 A100 A100两个

[傲雪星枫]

(AA\d+|A\d+)

[lanshs]

试试这个 ((?<!A)A\d+)

[xuzuning]

匹配 A100 和 AA100

$s = 'A100B200C300D400AA100BB3554CC45648DD4563';
$p = '/A+\d+/';
preg_match_all($p, $s, $m);
print_r($m);

Array
(
    [0] => Array
        (
            [0] => A100
            [1] => AA100
        )

)

仅匹配 A100

$p = '/(?<![A-Z])A\d+/';

Array
(
    [0] => Array
        (
            [0] => A100
        )

)

[傲雪星枫]

基数与数是什么关系？

[MUGOER]

如果是 基数1000 数1000 匹配 基数1000 与 数1000 了