正则表达式匹配主机名-不包括TLD [英] Regex match a hostname -- not including the TLD

问题描述

我需要匹配一个主机名-但是不想要tld:

I need to match a host name--but don't want the tld:

example.com =〜/regex/=>示例

example.com =~ /regex/ => example

sub.example.com =〜/regex/=> sub.example

sub.example.com =~ /regex/ => sub.example

sub.sub.example.com =〜/regex/=> sub.sub.example

sub.sub.example.com =~ /regex/ => sub.sub.example

对正则表达式有帮助吗?谢谢.

Any help with the regex? Thanks.

推荐答案

假设您的字符串格式正确，并且不包含协议[即 http://] ，您需要所有字符，但不包括最终.tld.

Assuming your string is correctly formatted and doesn't include things like protocol [i.e. http://], you need all characters up to but not including the final .tld.

所以这是最简单的方法.正则表达式的诀窍是不要使事情变得过于复杂:

So this is the simplest way to do this. The trick with regular expressions is not to overcomplicate things:

.*(?=\.\w+)

这基本上是说，请给我集合中的所有字符，后跟[例如] .xxx ，该字符基本上只会返回上一个周期之前的所有内容

This basically says, give me all characters in the set that is followed by [for example] .xxx, which will basically just return everything prior to the last period.

如果您没有提前查找，则可能最容易使用:

If you don't have lookahead, it would probably be easiest to use:

(\w+\.)+

这将为您提供一切，包括最后一个'.'.然后只修剪'.'.

which will give you everything up to and including the final '.' and then just trim the '.'.

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