使用正则表达式提取字符串？

Question

Sample Data:

+---------------------------------------------------------------------------------+
|refererurl                                                                       |
+---------------------------------------------------------------------------------+
|https://www.tesco.com/groceries/dfp/dfp-beaa1a3b14.html                          |
|https://www.tesco.com/groceries/dfp/dfp-beaa1a3b14.html                          |
|https://www.tesco.com/groceries/dfp/dfp-beaa1a3b14.html                          |
|https://www.tesco.com/groceries/dfp/dfp-beaa1a3b14.html                          |
|http://mbappgiwwg33nfz2gk43dn4xgo4tpmnsxe6joozuwk5y8.com/                        |
|http://mbappgewtgobzgu4dcmrtgy888888.com/                                        |
|https://www.tesco.com/groceries/dfp/dfp-beaa1a3b14.html                          |
|http://mbappgiwwg33nfz2gk43dn4xgo4tpmnsxe6joozuwk5y8.com/                        |
|https://www.tesco.com/groceries/dfp/dfp-beaa1a3b14.html                          |
|https://www.tesco.com/groceries/dfp/dfp-beaa1a3b14.html                          |
|null                        |
|https://www.tesco.com/groceries/dfp/dfp-beaa1a3b14.html                          |
|http://mbappgiwwg33nfz2gk43dn4xgo4tpmnsxe6joozuwk5y8.com/                        |
|https://www.tesco.com/groceries/dfp/dfp-beaa1a3b14.html                          |
|http://mbappgiwwg33nfz2gk43dn4xgo4tpmnsxe6joozuwk5y8.com/                        |
|https://www.tesco.com/direct/party-gifts-flowers/helium-canisters/cat31450037.cat|
|https://www.tesco.com/groceries/dfp/dfp-beaa1a3b14.html                          |
|https://www.tesco.com/groceries/dfp/dfp-beaa1a3b14.html                          |
|https://www.tesco.com/groceries/dfp/dfp-beaa1a3b14.html                          |
|https://www.tesco.com/groceries/dfp/dfp-beaa1a3b14.html                          |
+---------------------------------------------------------------------------------+

我想要正则表达式如下：

一个。我想要一个正则表达式，它可以在'.com'之前开始向后提取，直到网站名称包括.com 例如。 https://www.tesco.com/groceries/dfp/dfp-beaa1a3b14.html - > tesco.com http://mbappgiwwg33nfz2gk43dn4xgo4tpmnsxe6joozuwk5y8.com - > mbappgiwwg33nfz2gk43dn4xgo4tpmnsxe6joozuwk5y8.com

Answer 1

以下正则表达式似乎在这里工作：

[^.\/]+.com

Demo

请注意，这不考虑像tesco.co.uk.com这样的可能URL，在这种情况下我们需要做更多的工作。

Answer 2

试试这个：

(?:http(?:s)?:\/\/(?:www.)?)(.*?)\/

它甚至可以用于以下网址：www.example.co.uk/qsdqsd.html

DEMO