正则表达式 - 我做错了什么吗？

Question

This is javascript, but a virtually identical regex is failing in PHP too, so I don't think it's language specific

var r = new RegExp(
    "^(:19|20)?[0-9][0-9]"            // optional 19/20 start followed by 2 numbers
    + "-"                             // a hyphen
    + "(:0?[1-9]|1[0-2])"             // optional 0 followed by 1-9, or 10, 11, 12
    + "-"                             // a hyphen
    + "(:3[01]|[12][0-9]|0?[1-9])$"   // you get the idea.
);
r.test("2008-07-01");                // == false

What on earth am I missing?

Answer 1

我认为你的非捕获块应该是例如(?:19|20)而不是(:19|20)

Answer 2

Correct; your regular expression would actually work with ?:

? when used a prefix indicates that you're going to do something about capturing. Either not capture the block (:) , capture ahead (=) , behind (<=) , etc.