Regex-xpath-how to extract a substring from string?

[sathyarajg]

I have the following xpath match in my test suite,

//html/body/div[2]/table/tbody/tr[td/b[text()='NewsV1']]//td[4]/a[1]/@href[1]

Result : 

http://news.co.uk:10100/local-news-en-1.0/info

I want the result as http://news.co.uk:10100/ 

I tried the below xpath expression with reg ex,

concat(join(tokenize(//html/body/div[2]/table/tbody/tr[td/b[text()='NewsV1']]//td[4]/a[1]/@href[1], '/' )[position() < 4],'/'),'/')

This i am getting the error as invalid xpath expression.kindly suggest me why this xpath expression is incorrect and help me to form the correct syntax to get the substring properly.

I cant write this groovy script to get this..i am facing CDATA error because of http response.

So i want the suggestion for xpath+regex

Thanks for advance .same problem in ready API too

[PaulMS]

Unknown system function join() according to xpath tester

https://www.freeformatter.com/xpath-tester.html

Try string-join 

https://stackoverflow.com/questions/21996965/concatenate-multiple-node-values-in-xpath

or some other solutions here

https://stackoverflow.com/questions/12507388/regex-extract-a-substring-from-a-given-string