我正在使用来自 regexlib.com 的模式匹配 -
^(?=\d)(?:(?:31(?!.(?:0?[2469]|11))|(?:30|29)(?!.0?2)|29(?=.0?2.(?:(?:(?:1[6-9]|[2-9]\d)?(?:0[48]|[2468][048]|[13579][26])|(?:(?:16|[2468][048]|[3579][26])00)))(?:\x20|$))|(?:2[0-8]|1\d|0?[1-9]))([-./])(?:1[012]|0?[1-9])\1(?:1[6-9]|[2-9]\d)?\d\d(?:(?=\x20\d)\x20|$))?(((0?[1-9]|1[012])(:[0-5]\d){0,2}(\x20[AP]M))|([01]\d|2[0-3])(:[0-5]\d){1,2})?$
这似乎工作正常=>
val RE = """^(?=\d)(?:(?:31(?!.(?:0?[2469]|11))|(?:30|29)(?!.0?2)|29(?=.0?2.(?:(?:(?:1[6-9]|[2-9]\d)?(?:0[48]|[2468][048]|[13579][26])|(?:(?:16|[2468][048]|[3579][26])00)))(?:\x20|$))|(?:2[0-8]|1\d|0?[1-9]))([-./])(?:1[012]|0?[1-9])\1(?:1[6-9]|[2-9]\d)?\d\d(?:(?=\x20\d)\x20|$))?(((0?[1-9]|1[012])(:[0-5]\d){0,2}(\x20[AP]M))|([01]\d|2[0-3])(:[0-5]\d){1,2})?$""".r
RE.findAllMatchIn("31/12/2003 11:59:59 PM").foreach(println) //prints 31/12/2003 11:59:59 PM
RE.findAllMatchIn("31/122003 11:59:59 PM").foreach(println) //prints nothing
但是,我不能像这样直接匹配它 -
"31/12/2003 11:59:59 PM" match {
case RE(_) => println("Yes")
case _ => println("No")
}
这会打印“否”。我期待"is"
最佳答案
这是由于您在模式中有多个捕获组。您需要在第一种情况下使用 RE(_*)
来检查字符串是否匹配而不提取捕获组:
val RE = """^(?=\d)(?:(?:31(?!.(?:0?[2469]|11))|(?:30|29)(?!.0?2)|29(?=.0?2.(?:(?:(?:1[6-9]|[2-9]\d)?(?:0[48]|[2468][048]|[13579][26])|(?:(?:16|[2468][048]|[3579][26])00)))(?:\x20|$))|(?:2[0-8]|1\d|0?[1-9]))([-./])(?:1[012]|0?[1-9])\1(?:1[6-9]|[2-9]\d)?\d\d(?:(?=\x20\d)\x20|$))?(((0?[1-9]|1[012])(:[0-5]\d){0,2}(\x20[AP]M))|([01]\d|2[0-3])(:[0-5]\d){1,2})?$""".r
"31/12/2003 11:59:59 PM" match {
case RE(_*) => println("Yes")
case _ => println("No")
}
参见 Scala demo
关于regex - Scala 模式匹配,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/46621036/