Java matches doesn't match

Question

Could someone explain why the following statement in java returns false?

boolean results = "123/#".matches("\\d/#")

I tried to escape the forward slash and the pound sign, but this was being marked as redundant..

Answer 1

String.matches() in Java requires the full string to match the regex, as if it was bounded with ^ ... $ . So imagine that you're actually testing the regex ^\\d/#$ here.

To allow the string to contain anything else before/after, you must explicitly allow that in the regex using .* (anything), for example:

boolean results = "123/#".matches(".*\\d/#.*")

Answer 2

\\d匹配一个数字，如果要匹配1个或多个，则添加一个量词\\d+ 。

boolean results = "123/#".matches("\\d+/#")