Regex, exclude number starting with certain character

Question

I want to find number with don't proceed with £ character. Say I have a string:

"Gross Domestic Product in 2012 was £127 billion"

I want to return 2012 only.

I ve tried [^$][0-9]* but this only ignores $ character. Tried to match the whole word which starts and ends with number \b[0-9]*\b but \b applies only to [0-9a-zA-Z]

Any more suggestions?

Answer 1

One option which works (as tested using http://gskinner.com/RegExr) is:

(?<![£0-9])[0-9]+

This uses negative lookbehind to exclude £. The additional exclusion of 0-9 is to prevent it finding "27" in the above in addition to the "2012".