Question

I have a string like this:

http://www.example.com/value/1234/different-value

How can I extract the 1234?

Note: There may be a slash at the end:

http://www.example.com/value/1234/different-value
http://www.example.com/value/1234/different-value/

Answer 1

/([^/]+)(?=/[^/]+/?$)

should work. You might need to format it differently according to the language you’re using. For example, in Ruby, it’s

if subject =~ /\/([^\/]+)(?=\/[^\/]+\/?\Z)/
    match = $~[1]
else
    match = ""
end