正则表达式匹配不相等或不反转的数字组

我在这里指的是这个问题的后续：正则表达式匹配两个不相等的数字 https://stackoverflow.com/questions/5257685/regular-expression-to-match-two-numbers-that-are-not-equal

现在我的另一个问题场景是这样的：

P121324 - T  
P1212 - F - we got this covered in the message on link above (no same "sets")
P1221 - F - now new restriction - not even the reversed digits 12 - 21  

但是，现在的问题是P串可能会很长！ - 像这样：

P121315162324  

请注意，这是可以的，因为“集合”是：

12 13 14 15 16 23 24  

现在，我可以通过检查是否有重复来在代码（PHP）中做到这一点，但我想知道这是否可以使用单个正则表达式命令来完成？

尝试这个：

^P(?:([0-9])(?!\1)([0-9])(?!(?:..)*(?:\1\2|\2\1)))*$

如果您希望像上一个问题一样将数字限制为 [1-6]，请将 [0-9] 更改为 [1-6]。

看看它在线工作：rubular http://www.rubular.com/r/AGlyBYW9KW

以下是正则表达式的细分：

^          Start of string/line.
P          Literal P
(?:<snip>) Non-capturing group that matches a distinct pair of digits. See below.
*          Zero or more pairs (use + if you want to require at least one pair).
$          End of string/line.
  

的解释([0-9])(?!\1)([0-9])(?!(?:..)*(?:\1\2|\2\1))- 匹配一对：

([0-9])    Match and capture the first digit. Later refered to as \1.
(?!\1)     Negative lookahead. The next character must not be the same as \1.
([0-9])    Match and capture a digit. Later refered to as \2.
(?!<snip>) Negative lookahead. Check that the pair doesn't occur again.
  

的解释(?:..)*(?:\1\2|\2\1)- 尝试再次找到同一对：

(?:..)*       Match any number of pairs.
(?:\1\2|\2\1) Match either \1\2 or \2\1.