如何从不规则命名的字符串中提取网站名称？

Question

I have a column that looks like:

this contains no website
this is a web site.io
another websi te.co

I want to create a column that looks like:

NULL
site
te

So in the case of no period, it should return NULL, but if there is a period it should return the thing between the period and the previous space.

Answer 1

You can use a positive lookahead like this:

\S+(?=\.\S+)

The first \\S+ is what you want and the lookahead (?=\\.\\S+) is the suffix (eg .com , .org , .net , etc.).

Answer 2

You could go for:

\b(\w+)\.(?:io|co)\b

See a demo on regex101.com .